diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
new file mode 100644
index 0000000000..f89cfcb46c
--- /dev/null
+++ b/.github/workflows/build.yaml
@@ -0,0 +1,41 @@
+name: build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: setup-msys2
+        uses: msys2/setup-msys2@v2
+        with:
+          msystem: MSYS
+          update: true
+          install: msys2-devel base-devel autotools cocom diffutils gcc gettext-devel libiconv-devel make mingw-w64-cross-crt mingw-w64-cross-gcc mingw-w64-cross-zlib perl zlib-devel xmlto docbook-xsl
+
+      - name: Build
+        shell: msys2 {0}
+        run: |
+          # XXX: cygwin still uses gcc v11 so we get new warnings with v13,
+          # resulting in errors. We can't selectively disable warnigns since our
+          # cross compiler is also too old and doesn't understand the new
+          # warning flags, so we need to disable all errors for now.
+          export CXXFLAGS="-Wno-error -Wno-narrowing"
+          (cd winsup && ./autogen.sh)
+          ./configure --disable-dependency-tracking
+          make -j8
+
+      - name: Install
+        shell: msys2 {0}
+        run: |
+          make DESTDIR="$(pwd)"/_dest install
+
+      - name: Upload
+        uses: actions/upload-artifact@v3
+        with:
+          name: install
+          path: _dest/
diff --git a/.github/workflows/cygwin.yml b/.github/workflows/cygwin.yml
index 1610477d5e..dcd9a75c49 100644
--- a/.github/workflows/cygwin.yml
+++ b/.github/workflows/cygwin.yml
@@ -1,6 +1,6 @@
 name: cygwin
 
-on: push
+on: workflow_dispatch
 
 jobs:
   fedora-build:
diff --git a/.github/workflows/sync-with-cygwin.yml b/.github/workflows/sync-with-cygwin.yml
new file mode 100644
index 0000000000..57bd30e5da
--- /dev/null
+++ b/.github/workflows/sync-with-cygwin.yml
@@ -0,0 +1,24 @@
+name: sync-with-cygwin
+
+# File: .github/workflows/repo-sync.yml
+
+on:
+  workflow_dispatch:
+  schedule:
+  - cron:  "42 * * * *"
+jobs:
+  repo-sync:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+    - name: Fetch Cygwin's latest master and tags
+      run: |
+        git init --bare
+        # Potentially use git://sourceware.org/git/newlib-cygwin.git directly, but GitHub seems more reliable
+        git fetch https://github.com/cygwin/cygwin master:refs/heads/cygwin/master 'refs/tags/*:refs/tags/*'
+    - name: Push to our fork
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: |
+        git push https://$GITHUB_ACTOR:$GITHUB_TOKEN@github.com/$GITHUB_REPOSITORY refs/heads/cygwin/master 'refs/tags/*:refs/tags/*'
diff --git a/compile b/compile
index a85b723c7e..a4ecdb2519 100755
--- a/compile
+++ b/compile
@@ -53,7 +53,7 @@ func_file_conv ()
 	  MINGW*)
 	    file_conv=mingw
 	    ;;
-	  CYGWIN*)
+	  CYGWIN*|MSYS*)
 	    file_conv=cygwin
 	    ;;
 	  *)
@@ -67,7 +67,7 @@ func_file_conv ()
 	mingw/*)
 	  file=`cmd //C echo "$file " | sed -e 's/"\(.*\) " *$/\1/'`
 	  ;;
-	cygwin/*)
+	cygwin/*|msys/*)
 	  file=`cygpath -m "$file" || echo "$file"`
 	  ;;
 	wine/*)
diff --git a/config.guess b/config.guess
index 1972fda8eb..a922fa3881 100755
--- a/config.guess
+++ b/config.guess
@@ -914,6 +914,9 @@ EOF
     amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
 	echo x86_64-pc-cygwin
 	exit ;;
+    amd64:MSYS*:*:* | x86_64:MSYS*:*:*)
+	echo x86_64-unknown-msys
+	exit ;;
     prep*:SunOS:5.*:*)
 	echo powerpcle-unknown-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
diff --git a/config.rpath b/config.rpath
index 4dea75957c..4f12c27e02 100755
--- a/config.rpath
+++ b/config.rpath
@@ -109,7 +109,7 @@ hardcode_direct=no
 hardcode_minus_L=no
 
 case "$host_os" in
-  cygwin* | mingw* | pw32*)
+  cygwin* | msys* | mingw* | pw32*)
     # FIXME: the MSVC++ port hasn't been tested in a loooong time
     # When not using gcc, we currently assume that we are using
     # Microsoft Visual C++.
@@ -149,7 +149,7 @@ if test "$with_gnu_ld" = yes; then
         ld_shlibs=no
       fi
       ;;
-    cygwin* | mingw* | pw32*)
+    cygwin* | msys* | mingw* | pw32*)
       # hardcode_libdir_flag_spec is actually meaningless, as there is
       # no search path for DLLs.
       hardcode_libdir_flag_spec='-L$libdir'
@@ -268,7 +268,7 @@ else
       ;;
     bsdi4*)
       ;;
-    cygwin* | mingw* | pw32*)
+    cygwin* | msys* | mingw* | pw32*)
       # When not using gcc, we currently assume that we are using
       # Microsoft Visual C++.
       # hardcode_libdir_flag_spec is actually meaningless, as there is
@@ -437,7 +437,7 @@ case "$host_os" in
     ;;
   bsdi4*)
     ;;
-  cygwin* | mingw* | pw32*)
+  cygwin* | msys* | mingw* | pw32*)
     shrext=.dll
     ;;
   darwin* | rhapsody*)
diff --git a/config/dfp.m4 b/config/dfp.m4
index 5b29089cec..b03bcf0ccb 100644
--- a/config/dfp.m4
+++ b/config/dfp.m4
@@ -23,7 +23,8 @@ Valid choices are 'yes', 'bid', 'dpd', and 'no'.]) ;;
     powerpc*-*-linux* | i?86*-*-linux* | x86_64*-*-linux* | s390*-*-linux* | \
     i?86*-*-elfiamcu | i?86*-*-gnu* | \
     i?86*-*-mingw* | x86_64*-*-mingw* | \
-    i?86*-*-cygwin* | x86_64*-*-cygwin*)
+    i?86*-*-cygwin* | x86_64*-*-cygwin* | \
+    i?86*-*-msys* | x86_64*-*-msys*)
       enable_decimal_float=yes
       ;;
     *)
diff --git a/config/elf.m4 b/config/elf.m4
index 5f5cd88da0..b8491de764 100644
--- a/config/elf.m4
+++ b/config/elf.m4
@@ -15,7 +15,7 @@ AC_REQUIRE([AC_CANONICAL_TARGET])
 
 target_elf=no
 case $target in
-  *-darwin* | *-aix* | *-cygwin* | *-mingw* | *-aout* | *-*coff* | \
+  *-darwin* | *-aix* | *-cygwin* | *-msys* | *-mingw* | *-aout* | *-*coff* | \
   *-msdosdjgpp* | *-vms* | *-wince* | *-*-pe* | \
   alpha*-dec-osf* | hppa[[12]]*-*-hpux* | \
   nvptx-*-none)
diff --git a/config/lthostflags.m4 b/config/lthostflags.m4
index bc0f59ee79..ad977d43dc 100644
--- a/config/lthostflags.m4
+++ b/config/lthostflags.m4
@@ -13,7 +13,7 @@ AC_DEFUN([ACX_LT_HOST_FLAGS], [
 AC_REQUIRE([AC_CANONICAL_SYSTEM])
 
 case $host in
-  *-cygwin* | *-mingw*)
+  *-cygwin* | *-msys* | *-mingw*)
     # 'host' will be top-level target in the case of a target lib,
     # we must compare to with_cross_host to decide if this is a native
     # or cross-compiler and select where to install dlls appropriately.
diff --git a/config/mmap.m4 b/config/mmap.m4
index fba0d9d365..df2c778524 100644
--- a/config/mmap.m4
+++ b/config/mmap.m4
@@ -42,7 +42,7 @@ else
    # Systems known to be in this category are Windows (all variants),
    # VMS, and Darwin.
    case "$host_os" in
-     *vms* | cygwin* | pe | mingw* | darwin* | ultrix* | hpux10* | hpux11.00)
+     *vms* | cygwin* | msys* | pe | mingw* | darwin* | ultrix* | hpux10* | hpux11.00)
         gcc_cv_func_mmap_dev_zero=no ;;
      *)
         gcc_cv_func_mmap_dev_zero=yes;;
@@ -74,7 +74,7 @@ else
    # above for use of /dev/zero.
    # Systems known to be in this category are Windows, VMS, and SCO Unix.
    case "$host_os" in
-     *vms* | cygwin* | pe | mingw* | sco* | udk* )
+     *vms* | cygwin* | msys* | pe | mingw* | sco* | udk* )
         gcc_cv_func_mmap_anon=no ;;
      *)
         gcc_cv_func_mmap_anon=yes;;
diff --git a/config/picflag.m4 b/config/picflag.m4
index 614421d2a9..9d507ba3f8 100644
--- a/config/picflag.m4
+++ b/config/picflag.m4
@@ -25,6 +25,8 @@ case "${$2}" in
 	;;
     i[[34567]]86-*-cygwin* | x86_64-*-cygwin*)
 	;;
+    i[[34567]]86-*-msys* | x86_64-*-msys*)
+	;;
     i[[34567]]86-*-mingw* | x86_64-*-mingw*)
 	;;
     i[[34567]]86-*-nto-qnx*)
diff --git a/config/tcl.m4 b/config/tcl.m4
index 4542a4b23d..209bd8d9b8 100644
--- a/config/tcl.m4
+++ b/config/tcl.m4
@@ -33,7 +33,7 @@ AC_DEFUN([SC_PATH_TCLCONFIG], [
 
 	    # First check to see if --with-tcl was specified.
 	    case "${host}" in
-		*-*-cygwin*) platDir="win" ;;
+		*-*-cygwin* | *-*-msys*) platDir="win" ;;
 		*) platDir="unix" ;;
 	    esac
 	    if test x"${with_tclconfig}" != x ; then
@@ -165,7 +165,7 @@ AC_DEFUN([SC_PATH_TKCONFIG], [
 
 	    # then check for a private Tk library
 	    case "${host}" in
-		*-*-cygwin*) platDir="win" ;;
+		*-*-cygwin* | *-*-msys*) platDir="win" ;;
 		*) platDir="unix" ;;
 	    esac
 	    if test x"${ac_cv_c_tkconfig}" = x ; then
diff --git a/configure b/configure
index eb0ba840b1..0badc34cba 100755
--- a/configure
+++ b/configure
@@ -3074,7 +3074,7 @@ fi
 # Configure extra directories which are host specific
 
 case "${host}" in
-  *-cygwin*)
+  *-cygwin* | *-msys*)
     configdirs="$configdirs libtermcap" ;;
 esac
 
@@ -3595,7 +3595,7 @@ esac
 # Disable the go frontend on systems where it is known to not work. Please keep
 # this in sync with contrib/config-list.mk.
 case "${target}" in
-*-*-darwin* | *-*-cygwin* | *-*-mingw* | *-*-aix*)
+*-*-darwin* | *-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-aix*)
     unsupported_languages="$unsupported_languages go"
     ;;
 esac
@@ -3608,7 +3608,7 @@ if test x$enable_libgo = x; then
 	# PR 46986
 	noconfigdirs="$noconfigdirs target-libgo"
 	;;
-    *-*-cygwin* | *-*-mingw*)
+    *-*-cygwin* | *-*-msys* | *-*-mingw*)
 	noconfigdirs="$noconfigdirs target-libgo"
 	;;
     *-*-aix*)
@@ -3880,7 +3880,7 @@ case "${target}" in
   i[3456789]86-*-mingw*)
     target_configdirs="$target_configdirs target-winsup"
     ;;
-  *-*-cygwin*)
+  *-*-cygwin* | *-*-msys*)
     target_configdirs="$target_configdirs target-libtermcap target-winsup"
     noconfigdirs="$noconfigdirs target-libgloss"
     # always build newlib if winsup directory is present.
@@ -4024,7 +4024,7 @@ case "${host}" in
   i[3456789]86-*-msdosdjgpp*)
     host_makefile_frag="config/mh-djgpp"
     ;;
-  *-cygwin*)
+  *-cygwin* | *-msys*)
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking to see if cat works as expected" >&5
 $as_echo_n "checking to see if cat works as expected... " >&6; }
@@ -6192,7 +6192,7 @@ fi
 
 target_elf=no
 case $target in
-  *-darwin* | *-aix* | *-cygwin* | *-mingw* | *-aout* | *-*coff* | \
+  *-darwin* | *-aix* | *-cygwin* | *-msys* | *-mingw* | *-aout* | *-*coff* | \
   *-msdosdjgpp* | *-vms* | *-wince* | *-*-pe* | \
   alpha*-dec-osf* | hppa[12]*-*-hpux* | \
   nvptx-*-none)
@@ -6210,7 +6210,7 @@ if test $target_elf = yes; then :
 else
   if test x"$default_enable_lto" = x"yes" ; then
     case $target in
-      *-apple-darwin9* | *-cygwin* | *-mingw* | *djgpp*) ;;
+      *-apple-darwin9* | *-cygwin* | *-msys* | *-mingw* | *djgpp*) ;;
       # On other non-ELF platforms, LTO has yet to be validated.
       *) enable_lto=no ;;
     esac
@@ -6221,7 +6221,7 @@ else
   # warn during gcc/ subconfigure; unless you're bootstrapping with
   # -flto it won't be needed until after installation anyway.
     case $target in
-      *-cygwin* | *-mingw* | *-apple-darwin* | *djgpp*) ;;
+      *-cygwin* | *-msys* | *-mingw* | *-apple-darwin* | *djgpp*) ;;
       *) if test x"$enable_lto" = x"yes"; then
 	as_fn_error $? "LTO support is not enabled for this target." "$LINENO" 5
         fi
@@ -6231,7 +6231,7 @@ else
   # Among non-ELF, only Windows platforms support the lto-plugin so far.
   # Build it unless LTO was explicitly disabled.
   case $target in
-    *-cygwin* | *-mingw*) build_lto_plugin=$enable_lto ;;
+    *-cygwin* | *-msys* | *-mingw*) build_lto_plugin=$enable_lto ;;
     *) ;;
   esac
 
@@ -7102,7 +7102,7 @@ rm -f conftest*
 case "${host}" in
   *-*-hpux*) RPATH_ENVVAR=SHLIB_PATH ;;
   *-*-darwin*) RPATH_ENVVAR=DYLD_LIBRARY_PATH ;;
-  *-*-mingw* | *-*-cygwin ) RPATH_ENVVAR=PATH ;;
+  *-*-mingw* | *-*-cygwin | *-msys ) RPATH_ENVVAR=PATH ;;
   *) RPATH_ENVVAR=LD_LIBRARY_PATH ;;
 esac
 
@@ -7620,7 +7620,7 @@ case " $target_configdirs " in
   case " $target_configargs " in
   *" --with-newlib "*)
    case "$target" in
-    *-cygwin*)
+    *-cygwin* | *-msys*)
       FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(TARGET_SUBDIR)/winsup/cygwin -isystem $$s/winsup/cygwin/include'
       ;;
    esac
diff --git a/configure.ac b/configure.ac
index f1bb721006..f7fc8e974d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -409,7 +409,7 @@ AC_ARG_ENABLE(compressed_debug_sections,
 # Configure extra directories which are host specific
 
 case "${host}" in
-  *-cygwin*)
+  *-cygwin* | *-msys*)
     configdirs="$configdirs libtermcap" ;;
 esac
 
@@ -893,7 +893,7 @@ esac
 # Disable the go frontend on systems where it is known to not work. Please keep
 # this in sync with contrib/config-list.mk.
 case "${target}" in
-*-*-darwin* | *-*-cygwin* | *-*-mingw* | *-*-aix*)
+*-*-darwin* | *-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-aix*)
     unsupported_languages="$unsupported_languages go"
     ;;
 esac
@@ -906,7 +906,7 @@ if test x$enable_libgo = x; then
 	# PR 46986
 	noconfigdirs="$noconfigdirs target-libgo"
 	;;
-    *-*-cygwin* | *-*-mingw*)
+    *-*-cygwin* | *-*-msys* | *-*-mingw*)
 	noconfigdirs="$noconfigdirs target-libgo"
 	;;
     *-*-aix*)
@@ -1178,7 +1178,7 @@ case "${target}" in
   i[[3456789]]86-*-mingw*)
     target_configdirs="$target_configdirs target-winsup"
     ;;
-  *-*-cygwin*)
+  *-*-cygwin* | *-*-msys*)
     target_configdirs="$target_configdirs target-libtermcap target-winsup"
     noconfigdirs="$noconfigdirs target-libgloss"
     # always build newlib if winsup directory is present.
@@ -1322,7 +1322,7 @@ case "${host}" in
   i[[3456789]]86-*-msdosdjgpp*)
     host_makefile_frag="config/mh-djgpp"
     ;;
-  *-cygwin*)
+  *-cygwin* | *-msys*)
     ACX_CHECK_CYGWIN_CAT_WORKS
     host_makefile_frag="config/mh-cygwin"
     ;;
@@ -1809,7 +1809,7 @@ ACX_ELF_TARGET_IFELSE([# ELF platforms build the lto-plugin always.
   build_lto_plugin=yes
 ],[if test x"$default_enable_lto" = x"yes" ; then
     case $target in
-      *-apple-darwin9* | *-cygwin* | *-mingw* | *djgpp*) ;;
+      *-apple-darwin9* | *-cygwin* | *-msys* | *-mingw* | *djgpp*) ;;
       # On other non-ELF platforms, LTO has yet to be validated.
       *) enable_lto=no ;;
     esac
@@ -1820,7 +1820,7 @@ ACX_ELF_TARGET_IFELSE([# ELF platforms build the lto-plugin always.
   # warn during gcc/ subconfigure; unless you're bootstrapping with
   # -flto it won't be needed until after installation anyway.
     case $target in
-      *-cygwin* | *-mingw* | *-apple-darwin* | *djgpp*) ;;
+      *-cygwin*  | *-msys*| *-mingw* | *-apple-darwin* | *djgpp*) ;;
       *) if test x"$enable_lto" = x"yes"; then
 	AC_MSG_ERROR([LTO support is not enabled for this target.])
         fi
@@ -1830,7 +1830,7 @@ ACX_ELF_TARGET_IFELSE([# ELF platforms build the lto-plugin always.
   # Among non-ELF, only Windows platforms support the lto-plugin so far.
   # Build it unless LTO was explicitly disabled.
   case $target in
-    *-cygwin* | *-mingw*) build_lto_plugin=$enable_lto ;;
+    *-cygwin* | *-msys* | *-mingw*) build_lto_plugin=$enable_lto ;;
     *) ;;
   esac
 ])
@@ -2644,7 +2644,7 @@ rm -f conftest*
 case "${host}" in
   *-*-hpux*) RPATH_ENVVAR=SHLIB_PATH ;;
   *-*-darwin*) RPATH_ENVVAR=DYLD_LIBRARY_PATH ;;
-  *-*-mingw* | *-*-cygwin ) RPATH_ENVVAR=PATH ;;
+  *-*-mingw* | *-*-cygwin | *-*-msys ) RPATH_ENVVAR=PATH ;;
   *) RPATH_ENVVAR=LD_LIBRARY_PATH ;;
 esac
 
@@ -3157,7 +3157,7 @@ case " $target_configdirs " in
   case " $target_configargs " in
   *" --with-newlib "*)
    case "$target" in
-    *-cygwin*)
+    *-cygwin* | *-msys*)
       FLAGS_FOR_TARGET=$FLAGS_FOR_TARGET' -L$$r/$(TARGET_SUBDIR)/winsup/cygwin -isystem $$s/winsup/cygwin/include'
       ;;
    esac
diff --git a/libtool.m4 b/libtool.m4
index a216bb14e9..0d6d17a668 100644
--- a/libtool.m4
+++ b/libtool.m4
@@ -1521,7 +1521,7 @@ AC_CACHE_VAL([lt_cv_sys_max_cmd_len], [dnl
     lt_cv_sys_max_cmd_len=-1;
     ;;
 
-  cygwin* | mingw* | cegcc*)
+  cygwin* | msys* | mingw* | cegcc*)
     # On Win9x/ME, this test blows up -- it succeeds, but takes
     # about 5 minutes as the teststring grows exponentially.
     # Worse, since 9x/ME are not pre-emptively multitasking,
@@ -1763,7 +1763,7 @@ else
     lt_cv_dlopen_libs=
     ;;
 
-  cygwin*)
+  cygwin* | msys*)
     lt_cv_dlopen="dlopen"
     lt_cv_dlopen_libs=
     ;;
@@ -2234,14 +2234,14 @@ bsdi[[45]]*)
   # libtool to hard-code these into programs
   ;;
 
-cygwin* | mingw* | pw32* | cegcc*)
+cygwin* | msys* | mingw* | pw32* | cegcc*)
   version_type=windows
   shrext_cmds=".dll"
   need_version=no
   need_lib_prefix=no
 
   case $GCC,$host_os in
-  yes,cygwin* | yes,mingw* | yes,pw32* | yes,cegcc*)
+  yes,cygwin* | yes,msys* | yes,mingw* | yes,pw32* | yes,cegcc*)
     library_names_spec='$libname.dll.a'
     # DLL is installed to $(libdir)/../bin by postinstall_cmds
     postinstall_cmds='base_file=`basename \${file}`~
@@ -2262,6 +2262,12 @@ cygwin* | mingw* | pw32* | cegcc*)
     cygwin*)
       # Cygwin DLLs use 'cyg' prefix rather than 'lib'
       soname_spec='`echo ${libname} | sed -e 's/^lib/cyg/'``echo ${release} | $SED -e 's/[[.]]/-/g'`${versuffix}${shared_ext}'
+m4_if([$1], [],[
+      sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"])
+      ;;
+    msys*)
+      # Msys DLLs use 'msys-' prefix rather than 'lib'
+      soname_spec='`echo ${libname} | sed -e 's/^lib/msys-/'``echo ${release} | $SED -e 's/[[.]]/-/g'`${versuffix}${shared_ext}'
 m4_if([$1], [],[
       sys_lib_search_path_spec="$sys_lib_search_path_spec /usr/lib/w32api"])
       ;;
@@ -3021,7 +3027,7 @@ bsdi[[45]]*)
   lt_cv_file_magic_test_file=/shlib/libc.so
   ;;
 
-cygwin*)
+cygwin* | msys*)
   # func_win32_libid is a shell function defined in ltmain.sh
   lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
   lt_cv_file_magic_cmd='func_win32_libid'
@@ -3307,7 +3313,7 @@ AC_DEFUN([LT_LIB_M],
 [AC_REQUIRE([AC_CANONICAL_HOST])dnl
 LIBM=
 case $host in
-*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-haiku* | *-*-pw32* | *-*-darwin*)
+*-*-beos* | *-*-cegcc* | *-*-cygwin* | *-*-msys* | *-*-haiku* | *-*-pw32* | *-*-darwin*)
   # These system don't have libm, or don't need it
   ;;
 *-ncr-sysv4.3*)
@@ -3382,7 +3388,7 @@ case $host_os in
 aix*)
   symcode='[[BCDT]]'
   ;;
-cygwin* | mingw* | pw32* | cegcc*)
+cygwin* | msys* | mingw* | pw32* | cegcc*)
   symcode='[[ABCDGISTW]]'
   ;;
 hpux*)
@@ -3629,7 +3635,7 @@ m4_if([$1], [CXX], [
     beos* | irix5* | irix6* | nonstopux* | osf3* | osf4* | osf5*)
       # PIC is the default for these OSes.
       ;;
-    mingw* | cygwin* | os2* | pw32* | cegcc*)
+    mingw* | cygwin* | msys* | os2* | pw32* | cegcc*)
       # This hack is so that the source file can tell whether it is being
       # built for inclusion in a dll (and should export symbols for example).
       # Although the cygwin gcc ignores -fPIC, still need this for old-style
@@ -3942,7 +3948,7 @@ m4_if([$1], [CXX], [
       # PIC is the default for these OSes.
       ;;
 
-    mingw* | cygwin* | pw32* | os2* | cegcc*)
+    mingw* | cygwin* | msys* | pw32* | os2* | cegcc*)
       # This hack is so that the source file can tell whether it is being
       # built for inclusion in a dll (and should export symbols for example).
       # Although the cygwin gcc ignores -fPIC, still need this for old-style
@@ -4025,7 +4031,7 @@ m4_if([$1], [CXX], [
       fi
       ;;
 
-    mingw* | cygwin* | pw32* | os2* | cegcc*)
+    mingw* | cygwin* | msys* | pw32* | os2* | cegcc*)
       # This hack is so that the source file can tell whether it is being
       # built for inclusion in a dll (and should export symbols for example).
       m4_if([$1], [GCJ], [],
@@ -4258,7 +4264,7 @@ m4_if([$1], [CXX], [
   pw32*)
     _LT_TAGVAR(export_symbols_cmds, $1)="$ltdll_cmds"
   ;;
-  cygwin* | mingw* | cegcc*)
+  cygwin* | msys* | mingw* | cegcc*)
     _LT_TAGVAR(export_symbols_cmds, $1)='$NM $libobjs $convenience | $global_symbol_pipe | $SED -e '\''/^[[BCDGRS]][[ ]]/s/.*[[ ]]\([[^ ]]*\)/\1 DATA/;/^.*[[ ]]__nm__/s/^.*[[ ]]__nm__\([[^ ]]*\)[[ ]][[^ ]]*/\1 DATA/;/^I[[ ]]/d;/^[[AITW]][[ ]]/s/.* //'\'' | sort | uniq > $export_symbols'
   ;;
   *)
@@ -4310,7 +4316,7 @@ dnl Note also adjust exclude_expsyms for C++ above.
   extract_expsyms_cmds=
 
   case $host_os in
-  cygwin* | mingw* | pw32* | cegcc*)
+  cygwin* | msys* | mingw* | pw32* | cegcc*)
     # FIXME: the MSVC++ port hasn't been tested in a loooong time
     # When not using gcc, we currently assume that we are using
     # Microsoft Visual C++.
@@ -4425,7 +4431,7 @@ _LT_EOF
       fi
       ;;
 
-    cygwin* | mingw* | pw32* | cegcc*)
+    cygwin* | msys* | mingw* | pw32* | cegcc*)
       # _LT_TAGVAR(hardcode_libdir_flag_spec, $1) is actually meaningless,
       # as there is no search path for DLLs.
       _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
@@ -4798,7 +4804,7 @@ _LT_EOF
       _LT_TAGVAR(export_dynamic_flag_spec, $1)=-rdynamic
       ;;
 
-    cygwin* | mingw* | pw32* | cegcc*)
+    cygwin* | msys* | mingw* | pw32* | cegcc*)
       # When not using gcc, we currently assume that we are using
       # Microsoft Visual C++.
       # hardcode_libdir_flag_spec is actually meaningless, as there is
@@ -5742,7 +5748,7 @@ if test "$_lt_caught_CXX_error" != yes; then
         esac
         ;;
 
-      cygwin* | mingw* | pw32* | cegcc*)
+      cygwin* | msys* | mingw* | pw32* | cegcc*)
         # _LT_TAGVAR(hardcode_libdir_flag_spec, $1) is actually meaningless,
         # as there is no search path for DLLs.
         _LT_TAGVAR(hardcode_libdir_flag_spec, $1)='-L$libdir'
diff --git a/ltmain.sh b/ltmain.sh
index 9503ec85d7..307a33979e 100644
--- a/ltmain.sh
+++ b/ltmain.sh
@@ -976,7 +976,7 @@ func_enable_tag ()
 
 
   case $host in
-    *cygwin* | *mingw* | *pw32* | *cegcc* | *solaris2* )
+    *cygwin* | *msys* | *mingw* | *pw32* | *cegcc* | *solaris2* )
       # don't eliminate duplications in $postdeps and $predeps
       opt_duplicate_compiler_generated_deps=:
       ;;
@@ -1453,7 +1453,7 @@ func_mode_compile ()
 
     # On Cygwin there's no "real" PIC flag so we must build both object types
     case $host_os in
-    cygwin* | mingw* | pw32* | os2* | cegcc*)
+    cygwin* | msys* | mingw* | pw32* | os2* | cegcc*)
       pic_mode=default
       ;;
     esac
@@ -2279,7 +2279,7 @@ func_mode_install ()
 	      'exit $?'
 	  tstripme="$stripme"
 	  case $host_os in
-	  cygwin* | mingw* | pw32* | cegcc*)
+	  cygwin* | msys* | mingw* | pw32* | cegcc*)
 	    case $realname in
 	    *.dll.a)
 	      tstripme=""
@@ -2385,7 +2385,7 @@ func_mode_install ()
 
 	# Do a test to see if this is really a libtool program.
 	case $host in
-	*cygwin* | *mingw*)
+	*cygwin* | *msys* | *mingw*)
 	    if func_ltwrapper_executable_p "$file"; then
 	      func_ltwrapper_scriptname "$file"
 	      wrapper=$func_ltwrapper_scriptname_result
@@ -2460,7 +2460,7 @@ func_mode_install ()
 	# remove .exe since cygwin /usr/bin/install will append another
 	# one anyway
 	case $install_prog,$host in
-	*/usr/bin/install*,*cygwin*)
+	*/usr/bin/install*,*cygwin*|*/usr/bin/install*,*msys*)
 	  case $file:$destfile in
 	  *.exe:*.exe)
 	    # this is ok
@@ -2595,7 +2595,7 @@ extern \"C\" {
 	      $RM $export_symbols
 	      ${SED} -n -e '/^: @PROGRAM@ $/d' -e 's/^.* \(.*\)$/\1/p' < "$nlist" > "$export_symbols"
 	      case $host in
-	      *cygwin* | *mingw* | *cegcc* )
+	      *cygwin* | *msys* | *mingw* | *cegcc* )
                 echo EXPORTS > "$output_objdir/$outputname.def"
                 cat "$export_symbols" >> "$output_objdir/$outputname.def"
 	        ;;
@@ -2607,7 +2607,7 @@ extern \"C\" {
 	      $GREP -f "$output_objdir/$outputname.exp" < "$nlist" > "$nlist"T
 	      $MV "$nlist"T "$nlist"
 	      case $host in
-	        *cygwin* | *mingw* | *cegcc* )
+	        *cygwin* | *msys* | *mingw* | *cegcc* )
 	          echo EXPORTS > "$output_objdir/$outputname.def"
 	          cat "$nlist" >> "$output_objdir/$outputname.def"
 	          ;;
@@ -2663,7 +2663,7 @@ typedef struct {
 } lt_dlsymlist;
 "
 	  case $host in
-	  *cygwin* | *mingw* | *cegcc* )
+	  *cygwin* | *msys* | *mingw* | *cegcc* )
 	    echo >> "$output_objdir/$my_dlsyms" "\
 /* DATA imports from DLLs on WIN32 con't be const, because
    runtime relocations are performed -- see ld's documentation
@@ -2749,7 +2749,7 @@ static const void *lt_preloaded_setup() {
 	# Transform the symbol file into the correct name.
 	symfileobj="$output_objdir/${my_outputname}S.$objext"
 	case $host in
-	*cygwin* | *mingw* | *cegcc* )
+	*cygwin* | *msys* | *mingw* | *cegcc* )
 	  if test -f "$output_objdir/$my_outputname.def"; then
 	    compile_command=`$ECHO "$compile_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
 	    finalize_command=`$ECHO "$finalize_command" | $SED "s%@SYMFILE@%$output_objdir/$my_outputname.def $symfileobj%"`
@@ -3192,7 +3192,7 @@ func_to_host_path ()
             func_to_host_path_result=`( cmd //c echo "$1" ) 2>/dev/null |
               $SED -e 's/[ ]*$//' -e "$lt_sed_naive_backslashify"`
             ;;
-          *cygwin* )
+          *cygwin* | *msys* )
             func_to_host_path_result=`cygpath -w "$1" |
 	      $SED -e "$lt_sed_naive_backslashify"`
             ;;
@@ -3265,7 +3265,7 @@ func_to_host_pathlist ()
 	      ( cmd //c echo "$func_to_host_pathlist_tmp1" ) 2>/dev/null |
 	      $SED -e 's/[ ]*$//' -e "$lt_sed_naive_backslashify"`
             ;;
-          *cygwin* )
+          *cygwin* | *msys* )
             func_to_host_pathlist_result=`cygpath -w -p "$func_to_host_pathlist_tmp1" |
               $SED -e "$lt_sed_naive_backslashify"`
             ;;
@@ -3571,7 +3571,7 @@ main (int argc, char *argv[])
 	{
 EOF
 	    case "$host" in
-	      *mingw* | *cygwin* )
+	      *mingw* | *cygwin* | *msys* )
 		# make stdout use "unix" line endings
 		echo "          setmode(1,_O_BINARY);"
 		;;
@@ -4233,7 +4233,7 @@ func_mode_link ()
 {
     $opt_debug
     case $host in
-    *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+    *-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
       # It is impossible to link a dll without this setting, and
       # we shouldn't force the makefile maintainer to figure out
       # which system we are compiling for in order to pass an extra
@@ -4713,7 +4713,7 @@ func_mode_link ()
 	  ;;
 	esac
 	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	*-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
 	  testbindir=`$ECHO "$dir" | $SED 's*/lib$*/bin*'`
 	  case :$dllsearchpath: in
 	  *":$dir:"*) ;;
@@ -4733,7 +4733,7 @@ func_mode_link ()
       -l*)
 	if test "X$arg" = "X-lc" || test "X$arg" = "X-lm"; then
 	  case $host in
-	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	  *-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-beos* | *-cegcc* | *-*-haiku*)
 	    # These systems don't actually have a C or math library (as such)
 	    continue
 	    ;;
@@ -4813,7 +4813,7 @@ func_mode_link ()
 
       -no-install)
 	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-darwin* | *-cegcc*)
+	*-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-darwin* | *-cegcc*)
 	  # The PATH hackery in wrapper scripts is required on Windows
 	  # and Darwin in order for the loader to find any dlls it needs.
 	  func_warning "\`-no-install' is ignored for $host"
@@ -5772,7 +5772,7 @@ func_mode_link ()
 	if test -n "$library_names" &&
 	   { test "$use_static_libs" = no || test -z "$old_library"; }; then
 	  case $host in
-	  *cygwin* | *mingw* | *cegcc*)
+	  *cygwin* | *msys* | *mingw* | *cegcc*)
 	      # No point in relinking DLLs because paths are not encoded
 	      notinst_deplibs="$notinst_deplibs $lib"
 	      need_relink=no
@@ -5842,7 +5842,7 @@ func_mode_link ()
 	    elif test -n "$soname_spec"; then
 	      # bleh windows
 	      case $host in
-	      *cygwin* | mingw* | *cegcc*)
+	      *cygwin* | msys* | mingw* | *cegcc*)
 	        func_arith $current - $age
 		major=$func_arith_result
 		versuffix="-$major"
@@ -6693,7 +6693,7 @@ func_mode_link ()
       if test "$build_libtool_libs" = yes; then
 	if test -n "$rpath"; then
 	  case $host in
-	  *-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-beos* | *-cegcc* | *-*-haiku*)
+	  *-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-*-beos* | *-cegcc* | *-*-haiku*)
 	    # these systems don't actually have a c library (as such)!
 	    ;;
 	  *-*-rhapsody* | *-*-darwin1.[012])
@@ -7194,7 +7194,7 @@ EOF
 
 	orig_export_symbols=
 	case $host_os in
-	cygwin* | mingw* | cegcc*)
+	cygwin* | msys* | mingw* | cegcc*)
 	  if test -n "$export_symbols" && test -z "$export_symbols_regex"; then
 	    # exporting using user supplied symfile
 	    if test "x`$SED 1q $export_symbols`" != xEXPORTS; then
@@ -7710,7 +7710,7 @@ EOF
 
     prog)
       case $host in
-	*cygwin*) func_stripname '' '.exe' "$output"
+	*cygwin* | *msys*) func_stripname '' '.exe' "$output"
 	          output=$func_stripname_result.exe;;
       esac
       test -n "$vinfo" && \
@@ -7823,7 +7823,7 @@ EOF
 	  esac
 	fi
 	case $host in
-	*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
+	*-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-os2* | *-cegcc*)
 	  testbindir=`${ECHO} "$libdir" | ${SED} -e 's*/lib$*/bin*'`
 	  case :$dllsearchpath: in
 	  *":$libdir:"*) ;;
@@ -7901,7 +7901,7 @@ EOF
         # Disable wrappers for cegcc and mingw32ce hosts, we are cross compiling anyway.
         wrappers_required=no
         ;;
-      *cygwin* | *mingw* )
+      *cygwin* | *msys* | *mingw* )
         if test "$build_libtool_libs" != yes; then
           wrappers_required=no
         fi
@@ -8029,14 +8029,14 @@ EOF
 	esac
 	# test for cygwin because mv fails w/o .exe extensions
 	case $host in
-	  *cygwin*)
+	  *cygwin* | *msys*)
 	    exeext=.exe
 	    func_stripname '' '.exe' "$outputname"
 	    outputname=$func_stripname_result ;;
 	  *) exeext= ;;
 	esac
 	case $host in
-	  *cygwin* | *mingw* )
+	  *cygwin* | *msys* | *mingw* )
 	    func_dirname_and_basename "$output" "" "."
 	    output_name=$func_basename_result
 	    output_path=$func_dirname_result
@@ -8343,7 +8343,7 @@ EOF
 	  # tests/bindir.at for full details.
 	  tdlname=$dlname
 	  case $host,$output,$installed,$module,$dlname in
-	    *cygwin*,*lai,yes,no,*.dll | *mingw*,*lai,yes,no,*.dll | *cegcc*,*lai,yes,no,*.dll)
+	    *cygwin*,*lai,yes,no,*.dll | *msys*,*lai,yes,no,*.dll | *mingw*,*lai,yes,no,*.dll | *cegcc*,*lai,yes,no,*.dll)
 	      # If a -bindir argument was supplied, place the dll there.
 	      if test "x$bindir" != x ;
 	      then
diff --git a/ltoptions.m4 b/ltoptions.m4
index 5ef12ced2a..5e7bc34702 100644
--- a/ltoptions.m4
+++ b/ltoptions.m4
@@ -126,7 +126,7 @@ LT_OPTION_DEFINE([LT_INIT], [win32-dll],
 [enable_win32_dll=yes
 
 case $host in
-*-*-cygwin* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
+*-*-cygwin* | *-*-msys* | *-*-mingw* | *-*-pw32* | *-*-cegcc*)
   AC_CHECK_TOOL(AS, as, false)
   AC_CHECK_TOOL(DLLTOOL, dlltool, false)
   AC_CHECK_TOOL(OBJDUMP, objdump, false)
diff --git a/newlib/configure b/newlib/configure
index 0b6ec15e98..d3171b4f5b 100755
--- a/newlib/configure
+++ b/newlib/configure
@@ -4269,7 +4269,7 @@ else
 fi
 
 
-ac_ext=c
+:cn
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
diff --git a/newlib/configure.host b/newlib/configure.host
index 32d1436baa..4e4c393912 100644
--- a/newlib/configure.host
+++ b/newlib/configure.host
@@ -194,7 +194,7 @@ case "${host_cpu}" in
 	shared_machine_dir=shared_x86
 	# Don't use for these since they provide their own setjmp.
 	case ${host} in
-	*-*-sco* | *-*-cygwin*) 
+	*-*-sco* | *-*-cygwin* | *-*-msys*) 
 		;;
 	*) 
 		mach_add_setjmp=true
@@ -399,7 +399,7 @@ fi
 
 if [ "x${newlib_mb}" = "x" ]; then
 	case "${host}" in
-	  *-*-cygwin*)
+	  *-*-cygwin*|*-*-msys*)
 		newlib_mb=yes
 	  	;;
 	esac
@@ -418,7 +418,7 @@ fi
 # THIS TABLE IS ALPHA SORTED.  KEEP IT THAT WAY.
 
 case "${host}" in
-  *-*-cygwin*)
+  *-*-cygwin* | *-*-msys*)
 	posix_dir=posix
 	xdr_dir=xdr
 	;;
@@ -578,7 +578,7 @@ esac
 # THIS TABLE IS ALPHA SORTED.  KEEP IT THAT WAY.
 
 case "${host}" in
-  *-*-cygwin*)
+  *-*-cygwin* | *-*-msys*)
 	test -z "$cygwin_srcdir" && cygwin_srcdir="${abs_newlib_basedir}/../winsup/cygwin"
 	export cygwin_srcdir
 	default_newlib_io_c99_formats="yes"
diff --git a/winsup/Makefile.am b/winsup/Makefile.am
index 9efdd4cb17..0946152c76 100644
--- a/winsup/Makefile.am
+++ b/winsup/Makefile.am
@@ -8,7 +8,7 @@
 
 # This makefile requires GNU make.
 
-cygdocdir = $(datarootdir)/doc/Cygwin
+cygdocdir = $(datarootdir)/doc/Msys
 
 cygdoc_DATA = \
 	CYGWIN_LICENSE \
diff --git a/winsup/configure.ac b/winsup/configure.ac
index 132028d0df..59b77fe3ed 100644
--- a/winsup/configure.ac
+++ b/winsup/configure.ac
@@ -84,11 +84,10 @@ AM_CONDITIONAL(BUILD_DOC, [test $enable_doc != "no"])
 AC_CHECK_PROGS([DOCBOOK2XTEXI], [docbook2x-texi db2x_docbook2texi])
 if test -z "$DOCBOOK2XTEXI" ; then
     if test "x$enable_doc" != "xno"; then
-        AC_MSG_ERROR([docbook2texi is required to build documentation])
-    else
-        unset DOCBOOK2XTEXI
-        AM_MISSING_PROG([DOCBOOK2XTEXI], [docbook2texi])
+        AC_MSG_WARN([docbook2texi is required to build documentation])
     fi
+    unset DOCBOOK2XTEXI
+    AM_MISSING_PROG([DOCBOOK2XTEXI], [docbook2texi])
 fi
 
 AC_CHECK_PROGS([XMLTO], [xmlto])
@@ -106,6 +105,11 @@ if test "x$with_cross_bootstrap" != "xyes"; then
     test -n "$MINGW_CXX" || AC_MSG_ERROR([no acceptable MinGW g++ found in \$PATH])
     AC_CHECK_PROGS(MINGW_CC, ${target_cpu}-w64-mingw32-gcc)
     test -n "$MINGW_CC" || AC_MSG_ERROR([no acceptable MinGW gcc found in \$PATH])
+
+    AC_CHECK_PROGS(MINGW32_CC, i686-w64-mingw32-gcc)
+    test -n "$MINGW32_CC" || AC_MSG_ERROR([no acceptable mingw32 gcc found in \$PATH])
+    AC_CHECK_PROGS(MINGW64_CC, x86_64-w64-mingw32-gcc)
+    test -n "$MINGW64_CC" || AC_MSG_ERROR([no acceptable mingw64 gcc found in \$PATH])
 fi
 AM_CONDITIONAL(CROSS_BOOTSTRAP, [test "x$with_cross_bootstrap" != "xyes"])
 
@@ -125,6 +129,11 @@ AC_CHECK_LIB([sframe], [sframe_decode], [BFD_LIBS="${BFD_LIBS} -lsframe"])
 AC_CHECK_LIB([zstd], [ZSTD_isError], [BFD_LIBS="${BFD_LIBS} -lzstd"])
 AC_SUBST([BFD_LIBS])
 
+AC_CHECK_LIB([sframe], [sframe_decode],
+	     AC_MSG_NOTICE([Detected libsframe; Assuming that libbfd depends on it]), [true])
+
+AM_CONDITIONAL(HAVE_LIBSFRAME, [test "x$ac_cv_lib_sframe_sframe_decode" = "xyes"])
+
 AC_CONFIG_FILES([
     Makefile
     cygwin/Makefile
diff --git a/winsup/cygserver/Makefile.am b/winsup/cygserver/Makefile.am
index ec7a62240c..b0d5735a06 100644
--- a/winsup/cygserver/Makefile.am
+++ b/winsup/cygserver/Makefile.am
@@ -46,7 +46,7 @@ libcygserver_a_SOURCES = \
 
 libcygserver_a_CXXFLAGS = $(cygserver_flags)
 
-cygdocdir = $(datarootdir)/doc/Cygwin
+cygdocdir = $(datarootdir)/doc/Msys
 
 install-data-local:
 	@$(MKDIR_P) $(DESTDIR)$(cygdocdir)
diff --git a/winsup/cygserver/cygserver-config b/winsup/cygserver/cygserver-config
index 373bfd24dd..c902857ea7 100755
--- a/winsup/cygserver/cygserver-config
+++ b/winsup/cygserver/cygserver-config
@@ -86,7 +86,7 @@ done
 
 # Check if running on NT
 _sys="`uname`"
-_nt=`expr "${_sys}" : "CYGWIN_NT"`
+_nt=`expr "${_sys}" : "MSYS_NT"`
 
 # Check for running cygserver processes first.
 if ps -ef | grep -v grep | grep -q ${service_name}
@@ -178,7 +178,7 @@ then
     echo "Do you want to install cygserver as service?"
     if request "(Say \"no\" if it's already installed as service)"
     then
-      if ! cygrunsrv -I ${service_name} -d "CYGWIN cygserver" -p /usr/sbin/cygserver
+      if ! cygrunsrv -I ${service_name} -d "MSYS cygserver" -p /usr/sbin/cygserver
       then
         echo
 	echo "Installation of cygserver as service failed.  Please check the"
diff --git a/winsup/cygserver/transport_pipes.h b/winsup/cygserver/transport_pipes.h
index e101623d24..66272bc86c 100644
--- a/winsup/cygserver/transport_pipes.h
+++ b/winsup/cygserver/transport_pipes.h
@@ -11,7 +11,11 @@ details. */
 #ifndef _TRANSPORT_PIPES_H
 #define _TRANSPORT_PIPES_H
 
+#ifdef __MSYS__
+#define PIPE_NAME_PREFIX	L"\\\\.\\pipe\\msys-"
+#else
 #define PIPE_NAME_PREFIX	L"\\\\.\\pipe\\cygwin-"
+#endif
 #define PIPE_NAME_SUFFIX	L"-lpc"
 
 /* Named pipes based transport, for security on NT */
diff --git a/winsup/cygwin/Makefile.am b/winsup/cygwin/Makefile.am
index 167be8149a..ec782dc6b9 100644
--- a/winsup/cygwin/Makefile.am
+++ b/winsup/cygwin/Makefile.am
@@ -37,13 +37,13 @@ newlib_build=$(target_builddir)/newlib
 toollibdir=$(tooldir)/lib
 toolincludedir=$(tooldir)/include
 
-# Parameters used in building the cygwin.dll.
+# Parameters used in building the msys-2.0.dll.
 
-DLL_NAME=cygwin1.dll
-NEW_DLL_NAME=new-cygwin1.dll
-DEF_FILE=cygwin.def
-LIB_NAME=libcygwin.a
-TEST_LIB_NAME=libcygwin0.a
+DLL_NAME=msys-2.0.dll
+NEW_DLL_NAME=new-msys-2.0.dll
+DEF_FILE=msys.def
+LIB_NAME=libmsys-2.0.a
+TEST_LIB_NAME=libmsys0.a
 
 #
 # sources
@@ -303,6 +303,7 @@ DLL_FILES= \
 	miscfuncs.cc \
 	mktemp.cc \
 	msg.cc \
+	msys2_path_conv.cc \
 	mount.cc \
 	net.cc \
 	netdb.cc \
@@ -570,32 +571,31 @@ LIBSERVER = $(cygserver_blddir)/libcygserver.a
 $(LIBSERVER):
 	$(MAKE) -C $(cygserver_blddir) libcygserver.a
 
-# We build as cygwin0.dll and rename at install time to overcome native
+# We build as msys-2.0.dll and rename at install time to overcome native
 # rebuilding issues (we don't want the build tools to see a partially built
-# cygwin.dll and attempt to use it instead of the old one).
+# msys-2.0.dll and attempt to use it instead of the old one).
 
 # linker script
 LDSCRIPT=cygwin.sc
 $(LDSCRIPT): $(LDSCRIPT).in
 	$(AM_V_GEN)$(CC) -E - -P < $^ -o $@
 
-# cygwin dll
+# msys-2.0 dll
 $(NEW_DLL_NAME): $(LDSCRIPT) libdll.a $(VERSION_OFILES) $(LIBSERVER)\
 		  $(newlib_build)/libm.a $(newlib_build)/libc.a
 	$(AM_V_CXXLD)$(CXX) $(CXXFLAGS) \
 	-mno-use-libstdc-wrappers \
-	-Wl,--gc-sections -nostdlib -Wl,-T$(LDSCRIPT) \
-	-Wl,--dynamicbase -static \
-	-Wl,--heap=0 -Wl,--out-implib,cygdll.a -shared -o $@ \
+	-Wl,--gc-sections -nostdlib -Wl,-T$(LDSCRIPT) -static \
+	-Wl,--heap=0 -Wl,--out-implib,msysdll.a -shared -o $@ \
 	-e @DLL_ENTRY@ $(DEF_FILE) \
 	-Wl,-whole-archive libdll.a -Wl,-no-whole-archive \
 	$(VERSION_OFILES) \
 	$(LIBSERVER) \
 	$(newlib_build)/libm.a \
 	$(newlib_build)/libc.a \
-	-lgcc -lkernel32 -lntdll -Wl,-Map,cygwin.map
+	-lgcc -lkernel32 -lntdll -Wl,-Map,msys.map
 
-# cygwin import library
+# msys-2.0 import library
 toolopts=--cpu=@target_cpu@ --ar=@AR@ --as=@AS@ --nm=@NM@ --objcopy=@OBJCOPY@
 
 $(DEF_FILE): scripts/gendef cygwin.din
@@ -608,17 +608,18 @@ sigfe.s: $(DEF_FILE) tlsoffsets
 
 LIBCOS=$(addsuffix .o,$(basename $(LIB_FILES)))
 $(LIB_NAME): $(DEF_FILE) $(LIBCOS) | $(NEW_DLL_NAME)
-	$(AM_V_GEN)$(srcdir)/scripts/mkimport $(toolopts) $(NEW_FUNCTIONS) $@ cygdll.a $(wordlist 2,99,$^)
+	$(AM_V_GEN)$(srcdir)/scripts/mkimport $(toolopts) $(NEW_FUNCTIONS) $@ msysdll.a $(wordlist 2,99,$^)
 
-# cygwin import library used by testsuite
+# msys-2.0 import library used by testsuite
 $(TEST_LIB_NAME): $(LIB_NAME)
-	$(AM_V_GEN)perl -p -e 'BEGIN{binmode(STDIN); binmode(STDOUT);}; s/cygwin1/cygwin0/g' < $? > $@
+	$(AM_V_GEN)perl -p -e 'BEGIN{binmode(STDIN); binmode(STDOUT);}; s/msys-2.0/msys0/g' < $? > $@
 
 # sublibs
 # import libraries for some subset of symbols indicated by given objects
 speclib=\
 	$(srcdir)/scripts/speclib $(toolopts) \
 	--exclude='cygwin' \
+	--exclude='msys' \
 	--exclude='(?i:dll)' \
 	--exclude='reloc' \
 	--exclude='^main$$' \
@@ -665,7 +666,7 @@ all-local: $(LIB_NAME) $(TEST_LIB_NAME) $(SUBLIBS)
 clean-local:
 	-rm -f $(BUILT_SOURCES)
 	-rm -f $(DEF_FILE) sigfe.s
-	-rm -f cygwin.sc cygdll.a cygwin.map
+	-rm -f cygwin.sc msysdll.a msys.map
 	-rm -f $(NEW_DLL_NAME)
 	-rm -f $(LIB_NAME) $(TEST_LIB_NAME) $(SUBLIBS)
 	-rm -f version.cc
@@ -683,7 +684,7 @@ man_MANS = regex/regex.3 regex/regex.7
 install-exec-hook: install-libs
 install-data-local: install-headers install-ldif
 
-install-libs:
+install-libs: install-toollibDATA
 	@$(MKDIR_P) $(DESTDIR)$(bindir)
 	$(INSTALL_PROGRAM) $(NEW_DLL_NAME) $(DESTDIR)$(bindir)/$(DLL_NAME)
 	@$(MKDIR_P) $(DESTDIR)$(toollibdir)
@@ -709,7 +710,7 @@ install-ldif:
 uninstall-hook: uninstall-headers uninstall-ldif uninstall-libs
 
 uninstall-libs:
-	rm -f $(DESTDIR)$(bindir)/cygwin1.dll
+	rm -f $(DESTDIR)$(bindir)/msys-2.0.dll
 	rm -f $(DESTDIR)$(toollibdir)/libg.a
 
 uninstall-headers:
diff --git a/winsup/cygwin/crt0.c b/winsup/cygwin/crt0.c
index 1096e58970..3160df4491 100644
--- a/winsup/cygwin/crt0.c
+++ b/winsup/cygwin/crt0.c
@@ -9,12 +9,20 @@ details. */
 
 extern int main (int argc, char **argv);
 
+#ifdef __MSYS__
+void msys_crt0 (int (*main) (int, char **));
+#else
 void cygwin_crt0 (int (*main) (int, char **));
+#endif
 
 void
 mainCRTStartup ()
 {
+#ifdef __MSYS__
+  msys_crt0 (main);
+#else
   cygwin_crt0 (main);
+#endif
 
   /* These are never actually called.  They are just here to force the inclusion
      of things like -lbinmode.  */
diff --git a/winsup/cygwin/cygthread.cc b/winsup/cygwin/cygthread.cc
index 54918e7677..518d11fdf2 100644
--- a/winsup/cygwin/cygthread.cc
+++ b/winsup/cygwin/cygthread.cc
@@ -170,7 +170,7 @@ new (size_t)
       }
 
 #ifdef DEBUGGING
-  if (!getenv ("CYGWIN_FREERANGE_NOCHECK"))
+  if (!getenv ("MSYS_FREERANGE_NOCHECK"))
     api_fatal ("overflowed cygwin thread pool");
   else
     thread_printf ("overflowed cygwin thread pool");
diff --git a/winsup/cygwin/cygwin.din b/winsup/cygwin/cygwin.din
index c70380fe83..71f3a68deb 100644
--- a/winsup/cygwin/cygwin.din
+++ b/winsup/cygwin/cygwin.din
@@ -1,4 +1,4 @@
-LIBRARY "cygwin1.dll" BASE=0x180040000
+LIBRARY "msys-2.0.dll" BASE=0x180040000
 
 EXPORTS
 # Exported variables
@@ -401,8 +401,8 @@ cygwin_attach_handle_to_fd SIGFE
 cygwin_conv_path SIGFE
 cygwin_conv_path_list SIGFE
 cygwin_create_path SIGFE
-cygwin_detach_dll SIGFE_MAYBE
-cygwin_dll_init NOSIGFE
+msys_detach_dll SIGFE_MAYBE
+msys_dll_init NOSIGFE
 cygwin_internal NOSIGFE
 cygwin_logon_user SIGFE
 cygwin_posix_path_list_p NOSIGFE
diff --git a/winsup/cygwin/cygwin.sc.in b/winsup/cygwin/cygwin.sc.in
index 69526f5d8a..4dc5daed8d 100644
--- a/winsup/cygwin/cygwin.sc.in
+++ b/winsup/cygwin/cygwin.sc.in
@@ -1,6 +1,10 @@
 #ifdef __x86_64__
 OUTPUT_FORMAT(pei-x86-64)
+# ifdef __MSYS__
+SEARCH_DIR("/usr/x86_64-pc-msys/lib/w32api"); SEARCH_DIR("=/usr/lib/w32api");
+# else
 SEARCH_DIR("/usr/x86_64-pc-cygwin/lib/w32api"); SEARCH_DIR("=/usr/lib/w32api");
+# endif
 #else
 #error unimplemented for this target
 #endif
diff --git a/winsup/cygwin/dcrt0.cc b/winsup/cygwin/dcrt0.cc
index 130d652aac..d7a1b1a60b 100644
--- a/winsup/cygwin/dcrt0.cc
+++ b/winsup/cygwin/dcrt0.cc
@@ -154,12 +154,12 @@ isquote (char c)
 
 /* Step over a run of characters delimited by quotes */
 static /*__inline*/ char *
-quoted (char *cmd, int winshell)
+quoted (char *cmd, int winshell, int glob)
 {
   char *p;
   char quote = *cmd;
 
-  if (!winshell)
+  if (!winshell || !glob)
     {
       char *p;
       strcpy (cmd, cmd + 1);
@@ -169,8 +169,8 @@ quoted (char *cmd, int winshell)
     }
 
   const char *s = quote == '\'' ? "'" : "\\\"";
-  /* This must have been run from a Windows shell, so preserve
-     quotes for globify to play with later. */
+  /* This must have been run from a Windows shell and globbing is enabled,
+     so preserve quotes for globify to play with later. */
   while (*cmd && *++cmd)
     if ((p = strpbrk (cmd, s)) == NULL)
       {
@@ -236,10 +236,20 @@ globify (char *word, char **&argv, int &argc, int &argvlen)
 	char quote = *s;
 	while (*++s && *s != quote)
 	  {
+	    /* This used to be:
 	    if (dos_spec || *s != '\\')
-	      /* nothing */;
+	      // nothing
 	    else if (s[1] == quote || s[1] == '\\')
 	      s++;
+	    With commit message:
+	       dcrt0.cc (globify): Don't use \ quoting when apparently quoting a DOS path
+	       spec, even within a quoted string.
+	    But that breaks the "literal quotes" part of '"C:/test.exe SOME_VAR=\"literal quotes\""'
+	    giving:    'C:/test.exe SOME_VAR=\literal quotes\' (with \'s between each character)
+	    instead of 'C:/test.exe SOME_VAR="literal quotes"' (with \'s between each character)
+	    */
+	    if (*s == '\\' && (s[1] == quote || s[1] == '\\'))
+	      s++;
 	    *p++ = '\\';
 	    size_t cnt = isascii (*s) ? 1 : mbtowc (NULL, s, MB_CUR_MAX);
 	    if (cnt <= 1 || cnt == (size_t)-1)
@@ -291,7 +301,7 @@ globify (char *word, char **&argv, int &argc, int &argvlen)
 /* Build argv, argc from string passed from Windows.  */
 
 static void
-build_argv (char *cmd, char **&argv, int &argc, int winshell)
+build_argv (char *cmd, char **&argv, int &argc, int winshell, int glob)
 {
   int argvlen = 0;
   int nesting = 0;		// monitor "nesting" from insert_file
@@ -300,6 +310,8 @@ build_argv (char *cmd, char **&argv, int &argc, int winshell)
   argvlen = 0;
   argv = NULL;
 
+  debug_printf ("cmd = '%s', winshell = %d, glob = %d", cmd, winshell, glob);
+
   /* Scan command line until there is nothing left. */
   while (*cmd)
     {
@@ -325,7 +337,7 @@ build_argv (char *cmd, char **&argv, int &argc, int winshell)
 		 a Cygwin process, or if the word starts with a '@'.
 		 In this case, the insert_file function needs an unquoted
 		 DOS filename and globbing isn't performed anyway. */
-	      cmd = quoted (cmd, winshell && argc > 0 && *word != '@');
+	      cmd = quoted (cmd, winshell && argc > 0 && *word != '@', glob);
 	    }
 	  if (issep (*cmd))	// End of argument if space
 	    break;
@@ -351,7 +363,7 @@ build_argv (char *cmd, char **&argv, int &argc, int winshell)
 	}
 
       /* Add word to argv file after (optional) wildcard expansion. */
-      if (!winshell || !argc || !globify (word, argv, argc, argvlen))
+      if (!glob || !argc || !globify (word, argv, argc, argvlen))
 	{
 	  debug_printf ("argv[%d] = '%s'", argc, word);
 	  argv[argc++] = word;
@@ -376,12 +388,12 @@ check_sanity_and_sync (per_process *p)
 
   /* magic_biscuit must be SIZEOF_PER_PROCESS.  */
   if (p->magic_biscuit != SIZEOF_PER_PROCESS)
-    api_fatal ("Incompatible cygwin .dll -- incompatible per_process info %u != %u",
+    api_fatal ("Incompatible msys .dll -- incompatible per_process info %u != %u",
 	       p->magic_biscuit, SIZEOF_PER_PROCESS);
 
   /* Complain if incompatible API changes made */
   if (p->api_major > cygwin_version.api_major)
-    api_fatal ("cygwin DLL and APP are out of sync -- API version mismatch %u > %u",
+    api_fatal ("msys DLL and APP are out of sync -- API version mismatch %u > %u",
 	       p->api_major, cygwin_version.api_major);
 }
 
@@ -476,12 +488,12 @@ break_here ()
 static void
 initial_env ()
 {
-  if (GetEnvironmentVariableA ("CYGWIN_TESTING", NULL, 0))
+  if (GetEnvironmentVariableA ("MSYS_TESTING", NULL, 0))
     _cygwin_testing = 1;
 
 #ifdef DEBUGGING
   char buf[PATH_MAX];
-  if (GetEnvironmentVariableA ("CYGWIN_DEBUG", buf, sizeof (buf) - 1))
+  if (GetEnvironmentVariableA ("MSYS_DEBUG", buf, sizeof (buf) - 1))
     {
       char buf1[PATH_MAX];
       GetModuleFileName (NULL, buf1, PATH_MAX);
@@ -903,6 +915,7 @@ dll_crt0_1 (void *)
       /* Scan the command line and build argv.  Expand wildcards if not
 	 called from another cygwin process. */
       build_argv (line, __argv, __argc,
+		  NOTSTATE (myself, PID_CYGPARENT),
 		  NOTSTATE (myself, PID_CYGPARENT) && allow_glob);
 
       /* Convert argv[0] to posix rules if it's currently blatantly
@@ -1073,7 +1086,11 @@ dll_crt0 (per_process *uptr)
    See winsup/testsuite/cygload for an example of how to use cygwin1.dll
    from MSVC and non-cygwin MinGW applications.  */
 extern "C" void
+#ifdef __MSYS__
+msys_dll_init ()
+#else
 cygwin_dll_init ()
+#endif
 {
   static int _fmode;
 
@@ -1276,7 +1293,7 @@ multiple_cygwin_problem (const char *what, uintptr_t magic_version, uintptr_t ve
       return;
     }
 
-  if (GetEnvironmentVariableA ("CYGWIN_MISMATCH_OK", NULL, 0))
+  if (GetEnvironmentVariableA ("MSYS_MISMATCH_OK", NULL, 0))
     return;
 
   if (CYGWIN_VERSION_MAGIC_VERSION (magic_version) == version)
@@ -1296,7 +1313,7 @@ are unable to find another cygwin DLL.",
 void
 cygbench (const char *s)
 {
-  if (GetEnvironmentVariableA ("CYGWIN_BENCH", NULL, 0))
+  if (GetEnvironmentVariableA ("MSYS_BENCH", NULL, 0))
     small_printf ("%05u ***** %s : %10d\n", GetCurrentProcessId (), s, strace.microseconds ());
 }
 #endif
diff --git a/winsup/cygwin/dlfcn.cc b/winsup/cygwin/dlfcn.cc
index fb70524735..7367d29713 100644
--- a/winsup/cygwin/dlfcn.cc
+++ b/winsup/cygwin/dlfcn.cc
@@ -147,8 +147,13 @@ collect_basenames (pathfinder::basenamelist & basenames,
   /* If the basename starts with "lib", ... */
   if (!strncmp (basename, "lib", 3))
     {
+#ifdef __MSYS__
+      /* ... replace "lib" with "msys-", before ... */
+      basenames.appendv ("msys-", 5, basename+3, baselen-3, ext, extlen, NULL);
+#else
       /* ... replace "lib" with "cyg", before ... */
       basenames.appendv ("cyg", 3, basename+3, baselen-3, ext, extlen, NULL);
+#endif
     }
   /* ... using original basename with new suffix. */
   basenames.appendv (basename, baselen, ext, extlen, NULL);
diff --git a/winsup/cygwin/dll_init.cc b/winsup/cygwin/dll_init.cc
index b486eaa1f8..03e5191ec5 100644
--- a/winsup/cygwin/dll_init.cc
+++ b/winsup/cygwin/dll_init.cc
@@ -874,7 +874,11 @@ dll_dllcrt0_1 (VOID *x)
 }
 
 extern "C" void
+#ifdef __MSYS__
+msys_detach_dll (dll *)
+#else
 cygwin_detach_dll (dll *)
+#endif
 {
   HANDLE retaddr;
   if (_my_tls.isinitialized ())
diff --git a/winsup/cygwin/dtable.cc b/winsup/cygwin/dtable.cc
index 8ebd7b2115..2185a84805 100644
--- a/winsup/cygwin/dtable.cc
+++ b/winsup/cygwin/dtable.cc
@@ -992,9 +992,15 @@ handle_to_fn (HANDLE h, char *posix_fn)
       if (wcsncasecmp (w32, DEV_NAMED_PIPE, DEV_NAMED_PIPE_LEN) == 0)
 	{
 	  w32 += DEV_NAMED_PIPE_LEN;
+#ifdef __MSYS__
+	  if (wcsncmp (w32, L"msys-", WCLEN (L"msys-")) != 0)
+	    return false;
+	  w32 += WCLEN (L"msys-");
+#else
 	  if (wcsncmp (w32, L"cygwin-", WCLEN (L"cygwin-")) != 0)
 	    return false;
 	  w32 += WCLEN (L"cygwin-");
+#endif
 	  /* Check for installation key and trailing dash. */
 	  w32len = cygheap->installation_key.Length / sizeof (WCHAR);
 	  if (w32len
diff --git a/winsup/cygwin/environ.cc b/winsup/cygwin/environ.cc
index 008854a071..0899aa0d4a 100644
--- a/winsup/cygwin/environ.cc
+++ b/winsup/cygwin/environ.cc
@@ -36,12 +36,14 @@ static char **lastenviron;
 /* Parse CYGWIN options */
 
 static NO_COPY bool export_settings = false;
+static bool emptyenvvalues = true;
 
 enum settings
   {
     isfunc,
     setdword,
     setbool,
+    setnegbool,
     setbit
   };
 
@@ -88,6 +90,10 @@ set_winsymlinks (const char *buf)
   else if (ascii_strncasematch (buf, "native", 6))
     allow_winsymlinks = ascii_strcasematch (buf + 6, "strict")
 			? WSYM_nativestrict : WSYM_native;
+  else if (ascii_strncasematch (buf, "deepcopy", 8))
+    allow_winsymlinks = WSYM_deepcopy;
+  else
+    allow_winsymlinks = WSYM_sysfile;
 }
 
 /* The structure below is used to set up an array which is used to
@@ -122,6 +128,10 @@ static struct parse_thing
   {"wincmdln", {&wincmdln}, setbool, NULL, {{false}, {true}}},
   {"winsymlinks", {func: set_winsymlinks}, isfunc, NULL, {{0}, {0}}},
   {"disable_pcon", {&disable_pcon}, setbool, NULL, {{false}, {true}}},
+  {"enable_pcon", {&disable_pcon}, setnegbool, NULL, {{true}, {false}}},
+  {"winjitdebug", {&winjitdebug}, setbool, NULL, {{false}, {true}}},
+  {"nativeinnerlinks", {&nativeinnerlinks}, setbool, NULL, {{false}, {true}}},
+  {"emptyenvvalues", {&emptyenvvalues}, setbool, NULL, {{false}, {true}}},
   {NULL, {0}, setdword, 0, {{0}, {0}}}
 };
 
@@ -191,7 +201,11 @@ parse_options (const char *inbuf)
       if (export_settings)
 	{
 	  debug_printf ("%s", newbuf + 1);
+#ifdef __MSYS__
+	  setenv ("MSYS", newbuf + 1, 1);
+#else
 	  setenv ("CYGWIN", newbuf + 1, 1);
+#endif
 	}
       return;
     }
@@ -235,6 +249,13 @@ parse_options (const char *inbuf)
 		  *k->setting.b = !!strtol (eq, NULL, 0);
 		debug_printf ("%s%s", *k->setting.b ? "" : "no", k->name);
 		break;
+	      case setnegbool:
+		if (!istrue || !eq)
+		  *k->setting.b = k->values[istrue].i;
+		else
+		  *k->setting.b = !strtol (eq, NULL, 0);
+		debug_printf ("%s%s", !*k->setting.b ? "" : "no", k->name);
+		break;
 	      case setbit:
 		*k->setting.x &= ~k->values[istrue].i;
 		if (istrue || (eq && strtol (eq, NULL, 0)))
@@ -304,6 +325,8 @@ static win_env conv_envvars[] =
     {NL ("HOME="), NULL, NULL, env_path_to_posix, env_path_to_win32, false},
     {NL ("LD_LIBRARY_PATH="), NULL, NULL,
 			       env_plist_to_posix, env_plist_to_win32, true},
+    {NL ("ORIGINAL_PATH="), NULL, NULL, env_PATH_to_posix, env_plist_to_win32, true},
+    {NL ("SHELL="), NULL, NULL, env_path_to_posix, env_path_to_win32, true, true},
     {NL ("TMPDIR="), NULL, NULL, env_path_to_posix, env_path_to_win32, false},
     {NL ("TMP="), NULL, NULL, env_path_to_posix, env_path_to_win32, false},
     {NL ("TEMP="), NULL, NULL, env_path_to_posix, env_path_to_win32, false},
@@ -329,10 +352,10 @@ static const unsigned char conv_start_chars[256] =
     0,        0,        0,        0,        0,        0,        0,        0,
     /*  72 */
 /*  H         I         J         K         L         M         N         O */
-    WC,       0,        0,        0,        WC,       0,        0,        0,
+    WC,       0,        0,        0,        WC,       0,        0,        WC,
     /*  80 */
 /*  P         Q         R         S         T         U         V         W */
-    WC,       0,        0,        0,        WC,       0,        0,        0,
+    WC,       0,        0,        WC,       WC,       0,        0,        0,
     /*  88 */
 /*  x         Y         Z                                                   */
     0,        0,        0,        0,        0,        0,        0,        0,
@@ -361,6 +384,7 @@ win_env::operator = (struct win_env& x)
   toposix = x.toposix;
   towin32 = x.towin32;
   immediate = false;
+  skip_if_empty = x.skip_if_empty;
   return *this;
 }
 
@@ -382,6 +406,8 @@ win_env::add_cache (const char *in_posix, const char *in_native)
       native = (char *) realloc (native, namelen + 1 + strlen (in_native));
       stpcpy (stpcpy (native, name), in_native);
     }
+  else if (skip_if_empty && !*in_posix)
+    native = (char *) calloc(1, 1);
   else
     {
       tmp_pathbuf tp;
@@ -447,6 +473,8 @@ posify_maybe (char **here, const char *value, char *outenv)
     return;
 
   int len = strcspn (src, "=") + 1;
+  if (conv->skip_if_empty && !src[len])
+    return;
 
   /* Turn all the items from c:<foo>;<bar> into their
      mounted equivalents - if there is one.  */
@@ -650,7 +678,7 @@ _addenv (const char *name, const char *value, int overwrite)
   win_env *spenv;
   if ((spenv = getwinenv (envhere)))
     spenv->add_cache (value);
-  if (strcmp (name, "CYGWIN") == 0)
+  if (strcmp (name, "MSYS") == 0)
     parse_options (value);
 
   return 0;
@@ -753,6 +781,9 @@ static struct renv {
 } renv_arr[] = {
 	{ NL("COMMONPROGRAMFILES=") },		// 0
 	{ NL("COMSPEC=") },
+#ifdef __MSYS__
+	{ NL("MSYSTEM=") },			// 2
+#endif /* __MSYS__ */
 	{ NL("PATH=") },			// 2
 	{ NL("PROGRAMFILES=") },
 	{ NL("SYSTEMDRIVE=") },			// 4
@@ -764,10 +795,21 @@ static struct renv {
 #define RENV_SIZE (sizeof (renv_arr) / sizeof (renv_arr[0]))
 
 /* Set of first characters of the above list of variables. */
-static const char idx_arr[] = "CPSTW";
+static const char idx_arr[] =
+#ifdef __MSYS__
+	"CMPSTW";
+#else
+	"CPSTW";
+#endif
 /* Index into renv_arr at which the variables with this specific character
    starts. */
-static const int start_at[] = { 0, 2, 4, 6, 8 };
+static const int start_at[] = {
+#ifdef __MSYS__
+				0, 2, 3, 5, 7, 9
+#else
+				0, 2, 4, 6, 8
+#endif
+								};
 
 /* Turn environment variable part of a=b string into uppercase - for some
    environment variables only. */
@@ -834,7 +876,11 @@ environ_init (char **envp, int envc)
       environ = envp;
       if (envp_passed_in)
 	{
+#ifdef __MSYS__
+	  p = getenv ("MSYS");
+#else
 	  p = getenv ("CYGWIN");
+#endif
 	  if (p)
 	    parse_options (p);
 	}
@@ -880,9 +926,23 @@ win32env_to_cygenv (PWCHAR rawenv, bool posify)
       char *eq = strchrnul (newp, '=');
       ucenv (newp, eq);    /* uppercase env vars which need it */
       if (*newp == 'T' && strncmp (newp, "TERM=", 5) == 0)
-        sawTERM = 1;
+	    {
+	      /* backwards compatibility: override TERM=msys by TERM=cygwin */
+	      if (strcmp (newp + 5, "msys") == 0)
+		{
+		  free(newp);
+		  i--;
+		  continue;
+		}
+	      sawTERM = 1;
+	    }
+#ifdef __MSYS__
+      else if (*newp == 'M' && strncmp (newp, "MSYS=", 5) == 0)
+        parse_options (newp + 5);
+#else
       else if (*newp == 'C' && strncmp (newp, "CYGWIN=", 7) == 0)
         parse_options (newp + 7);
+#endif
       if (*eq && posify)
         posify_maybe (envp + i, *++eq ? eq : --eq, tmpbuf);
       debug_printf ("%p: %s", envp[i], envp[i]);
@@ -951,12 +1011,13 @@ struct spenv
 static NO_COPY spenv spenvs[] =
 {
 #ifdef DEBUGGING
-  {NL ("CYGWIN_DEBUG="), false, true, NULL},
+  {NL ("MSYS_DEBUG="), false, true, NULL},
 #endif
   {NL ("HOMEDRIVE="), false, false, &cygheap_user::env_homedrive},
   {NL ("HOMEPATH="), false, false, &cygheap_user::env_homepath},
   {NL ("LOGONSERVER="), false, false, &cygheap_user::env_logsrv},
   {NL ("PATH="), false, true, NULL},
+  {NL ("MSYSTEM="), true, true, NULL},
   {NL ("SYSTEMDRIVE="), false, true, NULL},
   {NL ("SYSTEMROOT="), true, true, &cygheap_user::env_systemroot},
   {NL ("USERDOMAIN="), false, false, &cygheap_user::env_domain},
@@ -1044,7 +1105,7 @@ env_compare (const void *key, const void *memb)
    to the child. */
 char **
 build_env (const char * const *envp, PWCHAR &envblock, int &envc,
-	   bool no_envblock, HANDLE new_token)
+	   bool no_envblock, HANDLE new_token, bool keep_posix)
 {
   PWCHAR cwinenv = NULL;
   size_t winnum = 0;
@@ -1130,6 +1191,10 @@ build_env (const char * const *envp, PWCHAR &envblock, int &envc,
 
   int tl = 0;
   char **pass_dstp;
+#ifdef __MSYS__
+  char *msys2_env_conv_excl_env = NULL;
+  size_t msys2_env_conv_excl_count = 0;
+#endif
   char **pass_env = (char **) alloca (sizeof (char *)
 				      * (n + winnum + SPENVS_SIZE + 1));
   /* Iterate over input list, generating a new environment list and refreshing
@@ -1137,6 +1202,32 @@ build_env (const char * const *envp, PWCHAR &envblock, int &envc,
   for (srcp = envp, dstp = newenv, pass_dstp = pass_env; *srcp; srcp++)
     {
       bool calc_tl = !no_envblock;
+#ifdef __MSYS__
+      if (ascii_strncasematch(*srcp, "MSYS=", 5))
+        {
+          parse_options (*srcp + 5);
+	}
+      else if (!keep_posix)
+        {
+          /* Don't pass timezone environment to non-msys applications */
+          if (ascii_strncasematch(*srcp, "TZ=", 3))
+            {
+              const char *v = *srcp + 3;
+              if (*v == ':')
+                goto next1;
+              for (; *v; v++)
+                if (!isalpha(*v) && !isdigit(*v) &&
+                    *v != '-' && *v != '+' && *v != ':')
+                  goto next1;
+            }
+          else if (ascii_strncasematch(*srcp, "MSYS2_ENV_CONV_EXCL=", 20))
+            {
+              msys2_env_conv_excl_env = (char*)alloca (strlen(&(*srcp)[20])+1);
+              strcpy (msys2_env_conv_excl_env, &(*srcp)[20]);
+              msys2_env_conv_excl_count = string_split_delimited (msys2_env_conv_excl_env, ';');
+            }
+        }
+#endif
       /* Look for entries that require special attention */
       for (unsigned i = 0; i < SPENVS_SIZE; i++)
 	if (!saw_spenv[i] && (*dstp = spenvs[i].retrieve (no_envblock, *srcp)))
@@ -1240,11 +1331,11 @@ build_env (const char * const *envp, PWCHAR &envblock, int &envc,
 	     Note that this doesn't stop invalid strings without '=' in it
 	     etc., but we're opting for speed here for now.  Adding complete
 	     checking would be pretty expensive. */
-	  if (len == 1 || !*rest)
+	  if (len == 1 || (!emptyenvvalues && !*rest))
 	    continue;
 
 	  /* See if this entry requires posix->win32 conversion. */
-	  conv = getwinenv (*srcp, rest, &temp);
+	  conv = !*rest ? NULL : getwinenv (*srcp, rest, &temp);
 	  if (conv)
 	    {
 	      p = conv->native;	/* Use win32 path */
@@ -1257,6 +1348,16 @@ build_env (const char * const *envp, PWCHAR &envblock, int &envc,
 		  saw_PATH = true;
 		}
 	    }
+#ifdef __MSYS__
+	  else if (!keep_posix && *rest) {
+	    char *win_arg = arg_heuristic_with_exclusions
+		   (*srcp, msys2_env_conv_excl_env, msys2_env_conv_excl_count);
+	    debug_printf("WIN32_PATH is %s", win_arg);
+	    p = cstrdup1(win_arg);
+	    if (win_arg != *srcp)
+	      free (win_arg);
+	  }
+#endif
 	  else
 	    p = *srcp;		/* Don't worry about it */
 
diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
index c3433ab947..b8430633f8 100644
--- a/winsup/cygwin/exceptions.cc
+++ b/winsup/cygwin/exceptions.cc
@@ -29,6 +29,7 @@ details. */
 #include "exception.h"
 #include "posix_timer.h"
 #include "gcc_seh.h"
+#include "cygwin/exit_process.h"
 
 /* Define macros for CPU-agnostic register access.  The _CX_foo
    macros are for access into CONTEXT, the _MC_foo ones for access into
@@ -495,14 +496,14 @@ try_to_debug ()
   PWCHAR rawenv = GetEnvironmentStringsW () ;
   for (PWCHAR p = rawenv; *p != L'\0'; p = wcschr (p, L'\0') + 1)
     {
-      if (wcsncmp (p, L"CYGWIN=", wcslen (L"CYGWIN=")) == 0)
+      if (wcsncmp (p, L"MSYS=", wcslen (L"MSYS=")) == 0)
 	{
 	  PWCHAR q = wcsstr (p, L"error_start") ;
 	  /* replace 'error_start=...' with '_rror_start=...' */
 	  if (q)
 	    {
 	      *q = L'_' ;
-	      SetEnvironmentVariableW (L"CYGWIN", p + wcslen (L"CYGWIN=")) ;
+	      SetEnvironmentVariableW (L"MSYS", p + wcslen (L"MSYS=")) ;
 	    }
 	  break;
 	}
@@ -1511,10 +1512,25 @@ sigpacket::process ()
 dosig:
   if (have_execed)
     {
-      sigproc_printf ("terminating captive process");
-      if (::cygheap->ctty)
-	::cygheap->ctty->cleanup_before_exit ();
-      TerminateProcess (ch_spawn, sigExeced = si.si_signo);
+      switch (si.si_signo)
+        {
+        case SIGUSR1:
+        case SIGUSR2:
+        case SIGCONT:
+        case SIGSTOP:
+        case SIGTSTP:
+        case SIGTTIN:
+        case SIGTTOU:
+          system_printf ("Suppressing signal %d to win32 process (pid %u)",
+              (int)si.si_signo, (unsigned int)GetProcessId(ch_spawn));
+          goto done;
+        default:
+          sigproc_printf ("terminating captive process");
+          if (::cygheap->ctty)
+	    ::cygheap->ctty->cleanup_before_exit ();
+          rc = exit_process_tree (ch_spawn, 128 + (sigExeced = si.si_signo));
+          goto done;
+        }
     }
   /* Dispatch to the appropriate function. */
   sigproc_printf ("signal %d, signal handler %p", si.si_signo, handler);
diff --git a/winsup/cygwin/external.cc b/winsup/cygwin/external.cc
index 582bab84f7..bb1c8a1c41 100644
--- a/winsup/cygwin/external.cc
+++ b/winsup/cygwin/external.cc
@@ -141,7 +141,7 @@ create_winenv (const char * const *env)
   int unused_envc;
   PWCHAR envblock = NULL;
   char **envp = build_env (env ?: environ, envblock, unused_envc, false,
-			   NULL);
+			   NULL, true);
   PWCHAR p = envblock;
 
   if (envp)
diff --git a/winsup/cygwin/fhandler/pipe.cc b/winsup/cygwin/fhandler/pipe.cc
index e231316683..283319cce8 100644
--- a/winsup/cygwin/fhandler/pipe.cc
+++ b/winsup/cygwin/fhandler/pipe.cc
@@ -671,7 +671,11 @@ fhandler_pipe::close ()
   return ret;
 }
 
+#ifdef __MSYS__
+#define PIPE_INTRO "\\\\.\\pipe\\msys-"
+#else
 #define PIPE_INTRO "\\\\.\\pipe\\cygwin-"
+#endif
 
 /* Create a pipe, and return handles to the read and write ends,
    just like CreatePipe, but ensure that the write end permits
diff --git a/winsup/cygwin/fhandler/pty.cc b/winsup/cygwin/fhandler/pty.cc
index aff899b1d8..dbeffc9e3f 100644
--- a/winsup/cygwin/fhandler/pty.cc
+++ b/winsup/cygwin/fhandler/pty.cc
@@ -927,7 +927,11 @@ fhandler_pty_slave::open (int flags, mode_t)
       pipe_reply repl;
       DWORD len;
 
+#ifdef __MSYS__
+      __small_sprintf (buf, "\\\\.\\pipe\\msys-%S-pty%d-master-ctl",
+#else
       __small_sprintf (buf, "\\\\.\\pipe\\cygwin-%S-pty%d-master-ctl",
+#endif
 		       &cygheap->installation_key, get_minor ());
       termios_printf ("dup handles via master control pipe %s", buf);
       if (!CallNamedPipe (buf, &req, sizeof req, &repl, sizeof repl,
@@ -1202,7 +1206,11 @@ fhandler_pty_slave::reset_switch_to_nat_pipe (void)
 		    {
 		      char pipe[MAX_PATH];
 		      __small_sprintf (pipe,
+#ifdef __MSYS__
+			       "\\\\.\\pipe\\msys-%S-pty%d-master-ctl",
+#else
 			       "\\\\.\\pipe\\cygwin-%S-pty%d-master-ctl",
+#endif
 			       &cygheap->installation_key, get_minor ());
 		      pipe_request req = { GetCurrentProcessId () };
 		      pipe_reply repl;
@@ -2081,7 +2089,11 @@ fhandler_pty_master::close ()
 	  pipe_reply repl;
 	  DWORD len;
 
+#ifdef __MSYS__
+	  __small_sprintf (buf, "\\\\.\\pipe\\msys-%S-pty%d-master-ctl",
+#else
 	  __small_sprintf (buf, "\\\\.\\pipe\\cygwin-%S-pty%d-master-ctl",
+#endif
 			   &cygheap->installation_key, get_minor ());
 	  acquire_output_mutex (mutex_timeout);
 	  if (master_ctl)
@@ -2988,7 +3000,11 @@ fhandler_pty_master::setup ()
 
   /* Create master control pipe which allows the master to duplicate
      the pty pipe handles to processes which deserve it. */
+#ifdef __MSYS__
+  __small_sprintf (buf, "\\\\.\\pipe\\msys-%S-pty%d-master-ctl",
+#else
   __small_sprintf (buf, "\\\\.\\pipe\\cygwin-%S-pty%d-master-ctl",
+#endif
 		   &cygheap->installation_key, unit);
   master_ctl = CreateNamedPipe (buf, PIPE_ACCESS_DUPLEX
 				     | FILE_FLAG_FIRST_PIPE_INSTANCE,
@@ -3904,7 +3920,11 @@ fhandler_pty_slave::transfer_input (tty::xfer_dir dir, HANDLE from, tty *ttyp,
     {
       char pipe[MAX_PATH];
       __small_sprintf (pipe,
+#ifdef __MSYS__
+		       "\\\\.\\pipe\\msys-%S-pty%d-master-ctl",
+#else
 		       "\\\\.\\pipe\\cygwin-%S-pty%d-master-ctl",
+#endif
 		       &cygheap->installation_key, ttyp->get_minor ());
       pipe_request req = { GetCurrentProcessId () };
       pipe_reply repl;
diff --git a/winsup/cygwin/fork.cc b/winsup/cygwin/fork.cc
index e553c015a3..0dac93f8a9 100644
--- a/winsup/cygwin/fork.cc
+++ b/winsup/cygwin/fork.cc
@@ -158,7 +158,7 @@ frok::child (volatile char * volatile here)
   char buf[80];
   /* This is useful for debugging fork problems.  Use gdb to attach to
      the pid reported here. */
-  if (GetEnvironmentVariableA ("CYGWIN_FORK_SLEEP", buf, sizeof (buf)))
+  if (GetEnvironmentVariableA ("MSYS_FORK_SLEEP", buf, sizeof (buf)))
     {
       small_printf ("Sleeping %d after fork, pid %u\n", atoi (buf), GetCurrentProcessId ());
       Sleep (atoi (buf));
diff --git a/winsup/cygwin/globals.cc b/winsup/cygwin/globals.cc
index aef4a687db..bb37ca27dd 100644
--- a/winsup/cygwin/globals.cc
+++ b/winsup/cygwin/globals.cc
@@ -57,6 +57,7 @@ enum winsym_t
   WSYM_nativestrict,
   WSYM_nfs,
   WSYM_sysfile,
+  WSYM_deepcopy
 };
 
 exit_states NO_COPY exit_state;
@@ -69,9 +70,11 @@ bool allow_glob = true;
 bool ignore_case_with_glob;
 bool pipe_byte = true; /* Default to byte mode so that C# programs work. */
 bool reset_com;
-bool wincmdln;
-winsym_t allow_winsymlinks = WSYM_default;
+bool wincmdln = true;
+winsym_t allow_winsymlinks = WSYM_deepcopy;
 bool disable_pcon;
+bool winjitdebug = false;
+bool nativeinnerlinks = true;
 
 bool NO_COPY in_forkee;
 
diff --git a/winsup/cygwin/hookapi.cc b/winsup/cygwin/hookapi.cc
index ee2edbafee..9f31a716c4 100644
--- a/winsup/cygwin/hookapi.cc
+++ b/winsup/cygwin/hookapi.cc
@@ -379,7 +379,11 @@ hook_or_detect_cygwin (const char *name, const void *fn, WORD& subsys, HANDLE h)
   for (PIMAGE_IMPORT_DESCRIPTOR pd = pdfirst; pd->FirstThunk; pd++)
     {
       if (!ascii_strcasematch (rva (PSTR, map ?: (char *) hm, pd->Name - delta),
+#ifdef __MSYS__
+			       "msys-2.0.dll"))
+#else
 			       "cygwin1.dll"))
+#endif
 	continue;
       if (!fn)
 	{
diff --git a/winsup/cygwin/include/cygwin/cygwin_dll.h b/winsup/cygwin/include/cygwin/cygwin_dll.h
index 1e4cf98ba5..b77598bb63 100644
--- a/winsup/cygwin/include/cygwin/cygwin_dll.h
+++ b/winsup/cygwin/include/cygwin/cygwin_dll.h
@@ -24,8 +24,8 @@ details. */
 CDECL_BEGIN								      \
   int Entry (HINSTANCE h, DWORD reason, void *ptr);	              \
   typedef int (*mainfunc) (int, char **, char **);			      \
-  extern PVOID cygwin_attach_dll (HMODULE, mainfunc);			      \
-  extern void cygwin_detach_dll (PVOID);				      \
+  extern PVOID msys_attach_dll (HMODULE, mainfunc);			      \
+  extern void msys_detach_dll (PVOID);				      \
 CDECL_END								      \
 									      \
 static HINSTANCE storedHandle;						      \
@@ -42,7 +42,7 @@ static int __dllMain (int a __attribute__ ((__unused__)),		      \
 									      \
 static PVOID dll_index;							      \
 									      \
-int _cygwin_dll_entry (HINSTANCE h, DWORD reason, void *ptr)	      \
+int _msys_dll_entry (HINSTANCE h, DWORD reason, void *ptr)	      \
 {									      \
   int ret;								      \
   ret = 1;								      \
@@ -55,7 +55,7 @@ int _cygwin_dll_entry (HINSTANCE h, DWORD reason, void *ptr)	      \
       storedReason = reason;						      \
       storedPtr = ptr;							      \
       __dynamically_loaded = (ptr == NULL);				      \
-      dll_index = cygwin_attach_dll (h, &__dllMain);			      \
+      dll_index = msys_attach_dll (h, &__dllMain);			      \
       if (dll_index == (PVOID) -1)					      \
 	ret = 0;							      \
     }									      \
@@ -66,7 +66,7 @@ int _cygwin_dll_entry (HINSTANCE h, DWORD reason, void *ptr)	      \
       ret = Entry (h, reason, ptr);					      \
       if (ret)								      \
       {									      \
-	cygwin_detach_dll (dll_index);					      \
+	msys_detach_dll (dll_index);					      \
 	dll_index = (PVOID) -1;						      \
       }									      \
     }									      \
diff --git a/winsup/cygwin/include/cygwin/exit_process.h b/winsup/cygwin/include/cygwin/exit_process.h
new file mode 100644
index 0000000000..0486a0c74a
--- /dev/null
+++ b/winsup/cygwin/include/cygwin/exit_process.h
@@ -0,0 +1,364 @@
+#ifndef EXIT_PROCESS_H
+#define EXIT_PROCESS_H
+
+/*
+ * This file contains functions to terminate a Win32 process, as gently as
+ * possible.
+ *
+ * If appropriate, we will attempt to emulate a console Ctrl event for the
+ * process. Otherwise we will fall back to terminating the process.
+ *
+ * As we do not want to export this function in the MSYS2 runtime, these
+ * functions are marked as file-local.
+ *
+ * The idea is to inject a thread into the given process that runs either
+ * kernel32!CtrlRoutine() (i.e. the work horse of GenerateConsoleCtrlEvent())
+ * for SIGINT (Ctrl+C) and SIGQUIT (Ctrl+Break), or ExitProcess() for SIGTERM.
+ * This is handled through the console helpers.
+ *
+ * For SIGKILL, we run TerminateProcess() without injecting anything, and this
+ * is also the fall-back when the previous methods are unavailable.
+ *
+ * Note: as kernel32.dll is loaded before any process, the other process and
+ * this process will have ExitProcess() at the same address. The same holds
+ * true for kernel32!CtrlRoutine(), of course, but it is an internal API
+ * function, so we cannot look it up directly. Instead, we launch
+ * getprocaddr.exe to find out and inject the remote thread.
+ *
+ * This function expects the process handle to have the access rights for
+ * CreateRemoteThread(): PROCESS_CREATE_THREAD, PROCESS_QUERY_INFORMATION,
+ * PROCESS_VM_OPERATION, PROCESS_VM_WRITE, and PROCESS_VM_READ.
+ *
+ * The idea for the injected remote thread comes from the Dr Dobb's article "A
+ * Safer Alternative to TerminateProcess()" by Andrew Tucker (July 1, 1999),
+ * http://www.drdobbs.com/a-safer-alternative-to-terminateprocess/184416547.
+ *
+ * The idea to use kernel32!CtrlRoutine for the other signals comes from
+ * SendSignal (https://github.com/AutoSQA/SendSignal/ and
+ * http://stanislavs.org/stopping-command-line-applications-programatically-with-ctrl-c-events-from-net/).
+ */
+
+#include <math.h>
+#include <wchar.h>
+
+#ifndef __INSIDE_CYGWIN__
+/* To help debugging via kill.exe */
+#define small_printf(...) fprintf (stderr, __VA_ARGS__)
+#endif
+
+static BOOL get_wow (HANDLE process, BOOL &is_wow, USHORT &process_arch);
+static int exit_process_tree (HANDLE main_process, int exit_code);
+
+static BOOL
+kill_via_console_helper (HANDLE process, wchar_t *function_name, int exit_code,
+                         DWORD pid)
+{
+  BOOL is_wow;
+  USHORT process_arch;
+  if (!get_wow (process, is_wow, process_arch))
+    {
+      return FALSE;
+    }
+
+  const char *name;
+  switch (process_arch)
+  {
+    case IMAGE_FILE_MACHINE_I386:
+      name = "/usr/libexec/getprocaddr32.exe";
+      break;
+    case IMAGE_FILE_MACHINE_AMD64:
+      name = "/usr/libexec/getprocaddr64.exe";
+      break;
+    /* TODO: provide exes for these */
+    case IMAGE_FILE_MACHINE_ARMNT:
+      name = "/usr/libexec/getprocaddrarm32.exe";
+      break;
+    case IMAGE_FILE_MACHINE_ARM64:
+      name = "/usr/libexec/getprocaddrarm64.exe";
+      break;
+    default:
+      return FALSE; /* what?!? */
+  }
+  wchar_t wbuf[PATH_MAX];
+
+  if (cygwin_conv_path (CCP_POSIX_TO_WIN_W, name, wbuf, PATH_MAX)
+      || GetFileAttributesW (wbuf) == INVALID_FILE_ATTRIBUTES)
+    return FALSE;
+
+  STARTUPINFOW si = {};
+  PROCESS_INFORMATION pi;
+  size_t len = wcslen (wbuf) + 1 /* space */ + wcslen (function_name)
+               + 1 /* space */ + 3 /* exit code */ + 1 /* space */
+               + 10 /* process ID, i.e. DWORD */ + 1 /* NUL */;
+  WCHAR cmd[len + 1];
+  WCHAR title[] = L"cygwin-console-helper";
+  DWORD process_exit;
+
+  swprintf (cmd, len + 1, L"%S %S %d %u", wbuf, function_name, exit_code,
+            pid);
+
+  si.cb = sizeof (si);
+  si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;
+  si.wShowWindow = SW_HIDE;
+  si.lpTitle = title;
+  si.hStdInput = si.hStdError = si.hStdOutput = INVALID_HANDLE_VALUE;
+
+  /* Create a new hidden process. */
+  if (!CreateProcessW (NULL, cmd, NULL, NULL, TRUE,
+                       CREATE_NO_WINDOW | CREATE_NEW_PROCESS_GROUP, NULL, NULL,
+                       &si, &pi))
+    {
+      return FALSE;
+    }
+  else
+    {
+      /* Wait for the process to complete for 10 seconds */
+      WaitForSingleObject (pi.hProcess, 10000);
+    }
+
+  if (!GetExitCodeProcess (pi.hProcess, &process_exit))
+    process_exit = -1;
+
+  CloseHandle (pi.hThread);
+  CloseHandle (pi.hProcess);
+
+  return process_exit == 0 ? TRUE : FALSE;
+}
+
+static int current_is_wow = -1;
+static int is_32_bit_os = -1;
+
+typedef BOOL (WINAPI * IsWow64Process2_t) (HANDLE, USHORT *, USHORT *);
+static bool wow64process2initialized = false;
+static IsWow64Process2_t pIsWow64Process2 /* = NULL */;
+
+typedef BOOL (WINAPI * GetProcessInformation_t) (HANDLE,
+                                                 PROCESS_INFORMATION_CLASS,
+                                                 LPVOID, DWORD);
+static bool getprocessinfoinitialized = false;
+static GetProcessInformation_t pGetProcessInformation /* = NULL */;
+
+static BOOL
+get_wow (HANDLE process, BOOL &is_wow, USHORT &process_arch)
+{
+  USHORT native_arch = IMAGE_FILE_MACHINE_UNKNOWN;
+  if (!wow64process2initialized)
+    {
+      pIsWow64Process2 = (IsWow64Process2_t)
+              GetProcAddress (GetModuleHandle ("KERNEL32"),
+                              "IsWow64Process2");
+      MemoryBarrier ();
+      wow64process2initialized = true;
+    }
+  if (!pIsWow64Process2)
+    {
+      if (is_32_bit_os == -1)
+        {
+          SYSTEM_INFO info;
+
+          GetNativeSystemInfo (&info);
+          if (info.wProcessorArchitecture == 0)
+            is_32_bit_os = 1;
+          else if (info.wProcessorArchitecture == 9)
+            is_32_bit_os = 0;
+          else
+            is_32_bit_os = -2;
+        }
+
+      if (current_is_wow == -1
+          && !IsWow64Process (GetCurrentProcess (), &current_is_wow))
+        current_is_wow = -2;
+
+      if (is_32_bit_os == -2 || current_is_wow == -2)
+        return FALSE;
+
+      if (!IsWow64Process (process, &is_wow))
+        return FALSE;
+
+      process_arch = is_32_bit_os || is_wow ? IMAGE_FILE_MACHINE_I386 :
+                                      IMAGE_FILE_MACHINE_AMD64;
+      return TRUE;
+    }
+
+  if (!pIsWow64Process2 (process, &process_arch, &native_arch))
+    return FALSE;
+
+  /* The value will be IMAGE_FILE_MACHINE_UNKNOWN if the target process
+   * is not a WOW64 process
+   */
+  if (process_arch == IMAGE_FILE_MACHINE_UNKNOWN)
+    {
+      struct /* _PROCESS_MACHINE_INFORMATION */
+        {
+          /* 0x0000 */ USHORT ProcessMachine;
+          /* 0x0002 */ USHORT Res0;
+          /* 0x0004 */ DWORD MachineAttributes;
+        } /* size: 0x0008 */ process_machine_info;
+
+      is_wow = FALSE;
+      /* However, x86_64 on ARM64 claims not to be WOW64, so we have to
+       * dig harder... */
+      if (!getprocessinfoinitialized)
+        {
+          pGetProcessInformation = (GetProcessInformation_t)
+                  GetProcAddress (GetModuleHandle ("KERNEL32"),
+                                  "GetProcessInformation");
+          MemoryBarrier ();
+          getprocessinfoinitialized = true;
+        }
+      /*#define ProcessMachineTypeInfo 9*/
+      if (pGetProcessInformation &&
+          pGetProcessInformation (process, (PROCESS_INFORMATION_CLASS)9,
+            &process_machine_info, sizeof (process_machine_info)))
+        process_arch = process_machine_info.ProcessMachine;
+      else
+        process_arch = native_arch;
+    }
+  else
+    {
+      is_wow = TRUE;
+    }
+  return TRUE;
+}
+
+/**
+ * Terminates the process corresponding to the process ID
+ *
+ * This way of terminating the processes is not gentle: the process gets
+ * no chance of cleaning up after itself (closing file handles, removing
+ * .lock files, terminating spawned processes (if any), etc).
+ */
+static int
+exit_process (HANDLE process, int exit_code)
+{
+  LPTHREAD_START_ROUTINE address = NULL;
+  DWORD pid = GetProcessId (process), code;
+  int signo = exit_code & 0x7f;
+  switch (signo)
+    {
+    case SIGINT:
+    case SIGQUIT:
+      /* We are not going to kill them but simply say that Ctrl+C
+      is pressed. If the processes want they can exit or else
+      just wait.*/
+      if (kill_via_console_helper (
+              process, L"CtrlRoutine",
+              signo == SIGINT ? CTRL_C_EVENT : CTRL_BREAK_EVENT, pid))
+        return 0;
+      /* fall-through */
+    case SIGTERM:
+      if (kill_via_console_helper (process, L"ExitProcess", exit_code, pid))
+        return 0;
+      break;
+    default:
+      break;
+    }
+
+  return int (TerminateProcess (process, exit_code));
+}
+
+#include <tlhelp32.h>
+#include <unistd.h>
+
+/**
+ * Terminates the process corresponding to the process ID and all of its
+ * directly and indirectly spawned subprocesses using the
+ * TerminateProcess() function.
+ */
+static int
+exit_process_tree (HANDLE main_process, int exit_code)
+{
+  HANDLE snapshot = CreateToolhelp32Snapshot (TH32CS_SNAPPROCESS, 0);
+  PROCESSENTRY32 entry;
+  DWORD pids[16384];
+  int max_len = sizeof (pids) / sizeof (*pids), i, len, ret = 0;
+  DWORD pid = GetProcessId (main_process);
+  int signo = exit_code & 0x7f;
+
+  pids[0] = pid;
+  len = 1;
+
+  /*
+   * Even if Process32First()/Process32Next() seem to traverse the
+   * processes in topological order (i.e. parent processes before
+   * child processes), there is nothing in the Win32 API documentation
+   * suggesting that this is guaranteed.
+   *
+   * Therefore, run through them at least twice and stop when no more
+   * process IDs were added to the list.
+   */
+  for (;;)
+    {
+      memset (&entry, 0, sizeof (entry));
+      entry.dwSize = sizeof (entry);
+
+      if (!Process32First (snapshot, &entry))
+        break;
+
+      int orig_len = len;
+      do
+        {
+          /**
+           * Look for the parent process ID in the list of pids to kill, and if
+           * found, add it to the list.
+           */
+          for (i = len - 1; i >= 0; i--)
+            {
+              if (pids[i] == entry.th32ProcessID)
+                break;
+              if (pids[i] != entry.th32ParentProcessID)
+                continue;
+
+              /* We found a process to kill; is it an MSYS2 process? */
+              pid_t cyg_pid = cygwin_winpid_to_pid (entry.th32ProcessID);
+              if (cyg_pid > -1)
+                {
+                  if (cyg_pid == getpgid (cyg_pid))
+                    kill (cyg_pid, signo);
+                  break;
+                }
+              pids[len++] = entry.th32ProcessID;
+              break;
+            }
+        }
+      while (len < max_len && Process32Next (snapshot, &entry));
+
+      if (orig_len == len || len >= max_len)
+        break;
+    }
+
+  CloseHandle (snapshot);
+
+  for (i = len - 1; i >= 0; i--)
+    {
+      HANDLE process;
+
+      if (!i)
+        process = main_process;
+      else
+        {
+          process = OpenProcess (
+              PROCESS_CREATE_THREAD | PROCESS_QUERY_INFORMATION
+                  | PROCESS_VM_OPERATION | PROCESS_VM_WRITE | PROCESS_VM_READ,
+              FALSE, pids[i]);
+          if (!process)
+            process = OpenProcess (
+                PROCESS_QUERY_LIMITED_INFORMATION | PROCESS_TERMINATE,
+                FALSE, pids[i]);
+        }
+      DWORD code;
+
+      if (process
+          && (!GetExitCodeProcess (process, &code) || code == STILL_ACTIVE))
+        {
+          if (!exit_process (process, exit_code))
+            ret = -1;
+        }
+      if (process && process != main_process)
+        CloseHandle (process);
+    }
+
+  return ret;
+}
+
+#endif
diff --git a/winsup/cygwin/include/cygwin/version.h b/winsup/cygwin/include/cygwin/version.h
index 79c7fc1c63..f3c93e1835 100644
--- a/winsup/cygwin/include/cygwin/version.h
+++ b/winsup/cygwin/include/cygwin/version.h
@@ -496,7 +496,11 @@ details. */
    names include the CYGWIN_VERSION_SHARED_DATA version as well as this
    identifier. */
 
+#ifdef __MSYS__
+#define CYGWIN_VERSION_DLL_IDENTIFIER	"msys-2.0"
+#else
 #define CYGWIN_VERSION_DLL_IDENTIFIER	"cygwin1"
+#endif
 
 /* The Cygwin mount table interface in the Win32 registry also has a version
    number associated with it in case that is changed in a non-backwards
@@ -512,7 +516,11 @@ details. */
 
 /* Identifiers used in the Win32 registry. */
 
+#ifdef __MSYS__
+#define CYGWIN_INFO_CYGWIN_REGISTRY_NAME "MSYS"
+#else
 #define CYGWIN_INFO_CYGWIN_REGISTRY_NAME "Cygwin"
+#endif
 #define CYGWIN_INFO_INSTALLATIONS_NAME   "Installations"
 
 /* The default cygdrive prefix. */
diff --git a/winsup/cygwin/include/sys/cygwin.h b/winsup/cygwin/include/sys/cygwin.h
index 2c5997b5e2..6383646cc7 100644
--- a/winsup/cygwin/include/sys/cygwin.h
+++ b/winsup/cygwin/include/sys/cygwin.h
@@ -60,6 +60,12 @@ extern ssize_t cygwin_conv_path_list (cygwin_conv_path_t what, const void *from,
    to one of the above values, or to ENOMEM if malloc fails. */
 extern void *cygwin_create_path (cygwin_conv_path_t what, const void *from);
 
+extern char * arg_heuristic_with_exclusions (char const * const arg,
+					     char const * exclusions,
+					     size_t exclusions_count);
+
+extern char * arg_heuristic (char const * const);
+
 extern pid_t cygwin_winpid_to_pid (int);
 extern int cygwin_posix_path_list_p (const char *);
 extern void cygwin_split_path (const char *, char *, char *);
diff --git a/winsup/cygwin/include/sys/utsname.h b/winsup/cygwin/include/sys/utsname.h
index d6b3be96f7..730cb731a5 100644
--- a/winsup/cygwin/include/sys/utsname.h
+++ b/winsup/cygwin/include/sys/utsname.h
@@ -17,7 +17,7 @@ extern "C" {
 
 struct utsname
 {
-  char sysname[_UTSNAME_LENGTH];
+  char sysname[_UTSNAME_LENGTH + 1];
   char nodename[_UTSNAME_LENGTH];
   char release[_UTSNAME_LENGTH];
   char version[_UTSNAME_LENGTH];
diff --git a/winsup/cygwin/lib/_cygwin_crt0_common.cc b/winsup/cygwin/lib/_cygwin_crt0_common.cc
index d356a50fba..801b6f91ca 100644
--- a/winsup/cygwin/lib/_cygwin_crt0_common.cc
+++ b/winsup/cygwin/lib/_cygwin_crt0_common.cc
@@ -73,7 +73,11 @@ struct per_process_cxx_malloc __cygwin_cxx_malloc =
    and then jump to the dll.  */
 
 int
+#ifdef __MSYS__
+_msys_crt0_common (MainFunc f, per_process *u)
+#else
 _cygwin_crt0_common (MainFunc f, per_process *u)
+#endif
 {
   per_process *newu = (per_process *) cygwin_internal (CW_USER_DATA);
   bool uwasnull;
diff --git a/winsup/cygwin/lib/crt0.h b/winsup/cygwin/lib/crt0.h
index e599b44934..e81750032b 100644
--- a/winsup/cygwin/lib/crt0.h
+++ b/winsup/cygwin/lib/crt0.h
@@ -13,7 +13,11 @@ extern "C" {
 #include "winlean.h"
 struct per_process;
 typedef int (*MainFunc) (int argc, char *argv[], char **env);
+#ifdef __MSYS__
+int _msys_crt0_common (MainFunc, struct per_process *);
+#else
 int _cygwin_crt0_common (MainFunc, struct per_process *);
+#endif
 PVOID dll_dllcrt0 (HMODULE, struct per_process *);
 
 #ifdef __cplusplus
diff --git a/winsup/cygwin/lib/cygwin_attach_dll.c b/winsup/cygwin/lib/cygwin_attach_dll.c
index 866bfd80fa..82679c4a97 100644
--- a/winsup/cygwin/lib/cygwin_attach_dll.c
+++ b/winsup/cygwin/lib/cygwin_attach_dll.c
@@ -15,10 +15,18 @@ details. */
 
 /* for a loaded dll */
 PVOID
+#ifdef __MSYS__
+msys_attach_dll (HMODULE h, MainFunc f)
+#else
 cygwin_attach_dll (HMODULE h, MainFunc f)
+#endif
 {
   static struct per_process u;
+#ifdef __MSYS__
+  (void) _msys_crt0_common (f, &u);
+#else
   (void) _cygwin_crt0_common (f, &u);
+#endif
 
   /* jump into the dll. */
   return dll_dllcrt0 (h, &u);
diff --git a/winsup/cygwin/lib/cygwin_crt0.c b/winsup/cygwin/lib/cygwin_crt0.c
index 7020a639dd..396447e52e 100644
--- a/winsup/cygwin/lib/cygwin_crt0.c
+++ b/winsup/cygwin/lib/cygwin_crt0.c
@@ -14,8 +14,16 @@ extern void _dll_crt0 ()
 
 /* for main module */
 void
+#ifdef __MSYS__
+msys_crt0 (MainFunc f)
+#else
 cygwin_crt0 (MainFunc f)
+#endif
 {
+#ifdef __MSYS__
+  _msys_crt0_common (f, NULL);
+#else
   _cygwin_crt0_common (f, NULL);
+#endif
   _dll_crt0 ();	/* Jump into the dll, never to return */
 }
diff --git a/winsup/cygwin/local_includes/cygserver_setpwd.h b/winsup/cygwin/local_includes/cygserver_setpwd.h
index fc1576b059..b2975111cf 100644
--- a/winsup/cygwin/local_includes/cygserver_setpwd.h
+++ b/winsup/cygwin/local_includes/cygserver_setpwd.h
@@ -12,7 +12,11 @@ details. */
 #include <sys/types.h>
 #include "cygserver.h"
 
+#ifdef __MSYS__
+#define CYGWIN_LSA_KEY_PREFIX	L"L$MSYS_"
+#else
 #define CYGWIN_LSA_KEY_PREFIX	L"L$CYGWIN_"
+#endif
 
 #ifndef __INSIDE_CYGWIN__
 class transport_layer_base;
diff --git a/winsup/cygwin/local_includes/environ.h b/winsup/cygwin/local_includes/environ.h
index 86e64a72f9..fd6ca466e8 100644
--- a/winsup/cygwin/local_includes/environ.h
+++ b/winsup/cygwin/local_includes/environ.h
@@ -21,7 +21,7 @@ struct win_env
     char *native;
     ssize_t (*toposix) (const void *, void *, size_t);
     ssize_t (*towin32) (const void *, void *, size_t);
-    bool immediate;
+    bool immediate, skip_if_empty;
     void add_cache (const char *in_posix, const char *in_native = NULL);
     const char * get_native () const {return native ? native + namelen : NULL;}
     const char * get_posix () const {return posix ? posix : NULL;}
@@ -34,7 +34,7 @@ win_env *getwinenv (const char *name, const char *posix = NULL, win_env * = NULL
 char *getwinenveq (const char *name, size_t len, int);
 
 char **build_env (const char * const *envp, PWCHAR &envblock,
-			  int &envc, bool need_envblock, HANDLE new_token);
+			  int &envc, bool need_envblock, HANDLE new_token, bool keep_posix);
 
 char **win32env_to_cygenv (PWCHAR rawenv, bool posify);
 
diff --git a/winsup/cygwin/local_includes/miscfuncs.h b/winsup/cygwin/local_includes/miscfuncs.h
index d52debad1a..c4dbe0235b 100644
--- a/winsup/cygwin/local_includes/miscfuncs.h
+++ b/winsup/cygwin/local_includes/miscfuncs.h
@@ -81,6 +81,8 @@ void backslashify (const char *, char *, bool);
 void slashify (const char *, char *, bool);
 #define isslash(c) ((c) == '/')
 
+size_t string_split_delimited (char * string, char delimiter);
+
 extern void transform_chars (PWCHAR, PWCHAR);
 extern inline void
 transform_chars (PUNICODE_STRING upath, USHORT start_idx)
diff --git a/winsup/cygwin/local_includes/mount.h b/winsup/cygwin/local_includes/mount.h
index 5bb84b9769..cb48a6840e 100644
--- a/winsup/cygwin/local_includes/mount.h
+++ b/winsup/cygwin/local_includes/mount.h
@@ -170,7 +170,6 @@ class mount_info
   mount_item mount[MAX_MOUNTS];
 
   static bool got_usr_bin;
-  static bool got_usr_lib;
   static int root_idx;
 
   /* cygdrive_prefix is used as the root of the path automatically
@@ -182,6 +181,8 @@ class mount_info
  private:
   int posix_sorted[MAX_MOUNTS];
   int native_sorted[MAX_MOUNTS];
+  int longest_posix_sorted[MAX_MOUNTS];
+  int shortest_native_sorted[MAX_MOUNTS];
 
  public:
   void init (bool);
diff --git a/winsup/cygwin/local_includes/winf.h b/winsup/cygwin/local_includes/winf.h
index b586934410..bc53cd1aa3 100644
--- a/winsup/cygwin/local_includes/winf.h
+++ b/winsup/cygwin/local_includes/winf.h
@@ -56,6 +56,10 @@ class av
 	calloced = 1;
       }
   }
+  void replace (int i, const char *arg)
+  {
+    argv[i] = cstrdup1 (arg);
+  }
   void dup_all ()
   {
     for (int i = calloced; i < argc; i++)
diff --git a/winsup/cygwin/miscfuncs.cc b/winsup/cygwin/miscfuncs.cc
index 767384faa9..160c996116 100644
--- a/winsup/cygwin/miscfuncs.cc
+++ b/winsup/cygwin/miscfuncs.cc
@@ -311,6 +311,26 @@ NT_readline::gets ()
     }
 }
 
+/* Searches through string for delimiter replacing each instance with '\0'
+   and returning the number of such delimited substrings. This function
+   Will return 0 for the NULL string and at least 1 otherwise. */
+
+size_t
+string_split_delimited (char * string, char delimiter)
+{
+  if ( string == NULL )
+      return 0;
+  size_t count = 1;
+  string = strchr ( string, delimiter );
+  while (string)
+    {
+      *string = '\0';
+      ++count;
+      string = strchr ( string + 1, delimiter );
+    }
+  return count;
+}
+
 /* Signal the thread name to any attached debugger
 
    (See "How to: Set a Thread Name in Native Code"
diff --git a/winsup/cygwin/mm/cygheap.cc b/winsup/cygwin/mm/cygheap.cc
index 4fda29d117..b1d5acb0fd 100644
--- a/winsup/cygwin/mm/cygheap.cc
+++ b/winsup/cygwin/mm/cygheap.cc
@@ -218,14 +218,22 @@ init_cygheap::init_installation_root ()
 
   /* Strip off last path component ("\\cygwin1.dll") */
   PWCHAR w = wcsrchr (installation_root_buf, L'\\');
+#ifdef __MSYS__
+  /* Back two folders to get root as we have all stuff in usr subfolder */
+  for (int i=1; i >=0; --i)
+  {
+#endif
   if (w)
     {
       *w = L'\0';
       w = wcsrchr (installation_root_buf, L'\\');
     }
   if (!w)
-    api_fatal ("Can't initialize Cygwin installation root dir.\n"
+    api_fatal ("Can't initialize MSYS2 installation root dir.\n"
 	       "Invalid DLL path");
+#ifdef __MSYS__
+  }
+#endif
 
   /* Copy result into installation_dir before stripping off "bin" dir and
      revert to Win32 path.  This path is added to the Windows environment
@@ -250,6 +258,7 @@ init_cygheap::init_installation_root ()
   RtlInitUnicodeString (&installation_root, installation_root_buf);
   RtlInitUnicodeString (&installation_dir, installation_dir_buf);
 
+#ifndef __MSYS__
   for (int i = 1; i >= 0; --i)
     {
       reg_key r (i, KEY_WRITE, _WIDE (CYGWIN_INFO_INSTALLATIONS_NAME),
@@ -258,6 +267,7 @@ init_cygheap::init_installation_root ()
 				    installation_root_buf)))
 	break;
     }
+#endif
 }
 
 /* Initialize bucket_val.  The value is the max size of a block
diff --git a/winsup/cygwin/mount.cc b/winsup/cygwin/mount.cc
index 14c1ac7294..37152fb95a 100644
--- a/winsup/cygwin/mount.cc
+++ b/winsup/cygwin/mount.cc
@@ -39,7 +39,6 @@ details. */
   (path_prefix_p (proc, (path), proc_len, false))
 
 bool NO_COPY mount_info::got_usr_bin;
-bool NO_COPY mount_info::got_usr_lib;
 int NO_COPY mount_info::root_idx = -1;
 
 /* is_native_path: Return non-zero if PATH starts with \??\[a-zA-Z] or
@@ -354,7 +353,6 @@ fs_info::update (PUNICODE_STRING upath, HANDLE in_vol)
 #define MINIMAL_WIN_NTFS_FLAGS (FILE_CASE_SENSITIVE_SEARCH \
 				| FILE_CASE_PRESERVED_NAMES \
 				| FILE_UNICODE_ON_DISK \
-				| FILE_PERSISTENT_ACLS \
 				| FILE_FILE_COMPRESSION \
 				| FILE_VOLUME_QUOTAS \
 				| FILE_SUPPORTS_SPARSE_FILES \
@@ -495,13 +493,13 @@ mount_info::create_root_entry (const PWCHAR root)
   sys_wcstombs (native_root, PATH_MAX, root);
   assert (*native_root != '\0');
   if (add_item (native_root, "/",
-		MOUNT_SYSTEM | MOUNT_IMMUTABLE | MOUNT_AUTOMATIC)
+		MOUNT_SYSTEM | MOUNT_IMMUTABLE | MOUNT_AUTOMATIC | MOUNT_NOACL)
       < 0)
     api_fatal ("add_item (\"%s\", \"/\", ...) failed, errno %d", native_root, errno);
   /* Create a default cygdrive entry.  Note that this is a user entry.
      This allows to override it with mount, unless the sysadmin created
      a cygdrive entry in /etc/fstab. */
-  cygdrive_flags = MOUNT_NOPOSIX | MOUNT_CYGDRIVE;
+  cygdrive_flags = MOUNT_NOPOSIX | MOUNT_CYGDRIVE | MOUNT_NOACL;
   strcpy (cygdrive, CYGWIN_INFO_CYGDRIVE_DEFAULT_PREFIX "/");
   cygdrive_len = strlen (cygdrive);
 }
@@ -521,22 +519,14 @@ mount_info::init (bool user_init)
   pathend = wcpcpy (pathend, L"\\etc\\fstab");
   from_fstab (user_init, path, pathend);
 
-  if (!user_init && (!got_usr_bin || !got_usr_lib))
+  if (!user_init && !got_usr_bin)
     {
       char native[PATH_MAX];
       if (root_idx < 0)
-	api_fatal ("root_idx %d, user_shared magic %y, nmounts %d", root_idx, user_shared->version, nmounts);
+        api_fatal ("root_idx %d, user_shared magic %y, nmounts %d", root_idx, user_shared->version, nmounts);
       char *p = stpcpy (native, mount[root_idx].native_path);
-      if (!got_usr_bin)
-      {
-	stpcpy (p, "\\bin");
-	add_item (native, "/usr/bin", MOUNT_SYSTEM | MOUNT_AUTOMATIC);
-      }
-      if (!got_usr_lib)
-      {
-	stpcpy (p, "\\lib");
-	add_item (native, "/usr/lib", MOUNT_SYSTEM | MOUNT_AUTOMATIC);
-      }
+      stpcpy (p, "\\usr\\bin");
+      add_item (native, "/bin", MOUNT_SYSTEM | MOUNT_AUTOMATIC | MOUNT_NOACL);
     }
 }
 
@@ -617,6 +607,7 @@ mount_info::conv_to_win32_path (const char *src_path, char *dst, device& dev,
   /* See if this is a cygwin "device" */
   if (win32_device_name (src_path, dst, dev))
     {
+      debug_printf ("win32_device_name (%s)", src_path);
       *flags = 0;
       rc = 0;
       goto out_no_chroot_check;
@@ -647,6 +638,7 @@ mount_info::conv_to_win32_path (const char *src_path, char *dst, device& dev,
     }
   if (isproc (src_path))
     {
+      debug_printf ("isproc (%s)", src_path);
       dev = *proc_dev;
       dev = fhandler_proc::get_proc_fhandler (src_path);
       if (dev == FH_NADA)
@@ -668,6 +660,7 @@ mount_info::conv_to_win32_path (const char *src_path, char *dst, device& dev,
      off the prefix and transform it into an MS-DOS path. */
   else if (iscygdrive (src_path))
     {
+      debug_printf ("iscygdrive (%s) mount_table->cygdrive %s", src_path, mount_table->cygdrive);
       int n = mount_table->cygdrive_len - 1;
       int unit;
 
@@ -679,11 +672,15 @@ mount_info::conv_to_win32_path (const char *src_path, char *dst, device& dev,
 	}
       else if (cygdrive_win32_path (src_path, dst, unit))
 	{
+	  debug_printf ("cygdrive_win32_path (%s)", src_path);
 	  *flags = cygdrive_flags;
 	  goto out;
 	}
       else if (mount_table->cygdrive_len > 1)
-	return ENOENT;
+      {
+		debug_printf ("mount_table->cygdrive_len > 1 (%s)", src_path);
+		return ENOENT;
+      }
     }
 
   int chroot_pathlen;
@@ -694,7 +691,9 @@ mount_info::conv_to_win32_path (const char *src_path, char *dst, device& dev,
       const char *path;
       int len;
 
-      mi = mount + posix_sorted[i];
+      mi = mount + shortest_native_sorted[i];
+      debug_printf (" mount[%d] .. checking %s -> %s ", i, mi->posix_path, mi->native_path);
+
       if (!cygheap->root.exists ()
 	  || (mi->posix_pathlen == 1 && mi->posix_path[0] == '/'))
 	{
@@ -934,7 +933,8 @@ mount_info::conv_to_posix_path (const char *src_path, char *posix_path,
   int pathbuflen = tail - pathbuf;
   for (int i = 0; i < nmounts; ++i)
     {
-      mount_item &mi = mount[native_sorted[i]];
+      mount_item &mi = mount[longest_posix_sorted[i]];
+      debug_printf (" mount[%d] .. checking %s -> %s ", i, mi.posix_path, mi.native_path);
       if (!path_prefix_p (mi.native_path, pathbuf, mi.native_pathlen,
 			  mi.flags & MOUNT_NOPOSIX))
 	continue;
@@ -954,6 +954,9 @@ mount_info::conv_to_posix_path (const char *src_path, char *posix_path,
 	nextchar = 1;
 
       int addslash = nextchar > 0 ? 1 : 0;
+      /* avoid appending a slash if the result already has a trailing slash */
+      if (append_slash && mi.posix_pathlen && mi.posix_path[mi.posix_pathlen-1] == '/')
+	append_slash = addslash = 0;
       if ((mi.posix_pathlen + (pathbuflen - mi.native_pathlen) + addslash) >= NT_MAX_PATH)
 	return ENAMETOOLONG;
       strcpy (posix_path, mi.posix_path);
@@ -1147,8 +1150,17 @@ mount_info::from_fstab_line (char *line, bool user)
   if (!*c)
     return true;
   cend = find_ws (c);
-  *cend = '\0';
   posix_path = conv_fstab_spaces (c);
+  if (!*cend)
+   {
+     unsigned mount_flags = MOUNT_SYSTEM | MOUNT_NOPOSIX | MOUNT_NOACL;
+
+     int res = mount_table->add_item (native_path, posix_path, mount_flags);
+     if (res && get_errno () == EMFILE)
+       return false;
+     return true;
+   }
+  *cend = '\0';
   /* Third field: FS type. */
   c = skip_ws (cend + 1);
   if (!*c)
@@ -1377,16 +1389,145 @@ sort_by_native_name (const void *a, const void *b)
   return res;
 }
 
+/* sort_by_longest_posix_name: qsort callback to sort the mount entries.
+   Sort user mounts ahead of system mounts to the same POSIX path. */
+/* FIXME: should the user should be able to choose whether to
+   prefer user or system mounts??? */
+static int
+sort_by_longest_posix_name (const void *a, const void *b)
+{
+  mount_item *ap = mounts_for_sort + (*((int*) a));
+  mount_item *bp = mounts_for_sort + (*((int*) b));
+
+  /* Base weighting on the conversion that would give the longest
+     posix path. */
+  ssize_t alen = (ssize_t) strlen (ap->posix_path) - (ssize_t) strlen (ap->native_path);
+  ssize_t blen = (ssize_t) strlen (bp->posix_path) - (ssize_t) strlen (bp->native_path);
+
+  int res = blen - alen;
+
+  if (res)
+    return res;		/* Path lengths differed */
+
+  /* The two paths were the same length, so just determine normal
+     lexical sorted order. */
+  res = strcmp (ap->posix_path, bp->posix_path);
+
+  if (res == 0)
+   {
+     /* need to select between user and system mount to same POSIX path */
+     if (!(bp->flags & MOUNT_SYSTEM))	/* user mount */
+      return 1;
+     else
+      return -1;
+   }
+
+  return res;
+}
+
+/* sort_by_shortest_native_name: qsort callback to sort the mount entries.
+   Sort user mounts ahead of system mounts to the same POSIX path. */
+/* FIXME: should the user should be able to choose whether to
+   prefer user or system mounts??? */
+static int
+sort_by_shortest_native_name (const void *a, const void *b)
+{
+  mount_item *ap = mounts_for_sort + (*((int*) a));
+  mount_item *bp = mounts_for_sort + (*((int*) b));
+
+  /* Base weighting on the conversion that would give the shortest
+     native path. */
+  ssize_t alen = (ssize_t) strlen (ap->native_path);
+  ssize_t blen = (ssize_t) strlen (bp->native_path);
+
+  int res = alen - blen;
+
+  if (res)
+    return res;		/* Path lengths differed */
+
+  /* The two paths were the same length, so just determine normal
+     lexical sorted order. */
+  res = strcmp (ap->native_path, bp->native_path);
+
+  if (res == 0)
+   {
+     /* need to select between user and system mount to same POSIX path */
+     if (!(bp->flags & MOUNT_SYSTEM))	/* user mount */
+      return 1;
+     else
+      return -1;
+   }
+
+  return res;
+}
+
+static int
+sort_posix_subdirs_before_parents (const void *a, const void *b)
+{
+    mount_item *ap = mounts_for_sort + (*((int*) a));
+    mount_item *bp = mounts_for_sort + (*((int*) b));
+
+    if (ap->posix_pathlen > bp->posix_pathlen)
+    {
+        if (!memcmp (bp->posix_path, ap->posix_path, bp->posix_pathlen))
+        {
+            // bp is a subdir of ap (bp must be moved in-front)
+            return -1;
+        }
+    }
+    else if (ap->posix_pathlen < bp->posix_pathlen)
+    {
+        if (!memcmp (ap->posix_path, bp->posix_path, ap->posix_pathlen))
+        {
+            // ap is a subdir of bp (good as we are)
+            return 1;
+        }
+    }
+    return 0;
+}
+
+#define DISABLE_NEW_STUFF 0
+#define ONLY_USE_NEW_STUFF 1
+
 void
 mount_info::sort ()
 {
   for (int i = 0; i < nmounts; i++)
-    native_sorted[i] = posix_sorted[i] = i;
+    native_sorted[i] = posix_sorted[i] = shortest_native_sorted[i] = longest_posix_sorted[i] = i;
   /* Sort them into reverse length order, otherwise we won't
      be able to look for /foo in /.  */
   mounts_for_sort = mount;	/* ouch. */
   qsort (posix_sorted, nmounts, sizeof (posix_sorted[0]), sort_by_posix_name);
   qsort (native_sorted, nmounts, sizeof (native_sorted[0]), sort_by_native_name);
+  qsort (longest_posix_sorted, nmounts, sizeof (longest_posix_sorted[0]), sort_by_longest_posix_name);
+  qsort (shortest_native_sorted, nmounts, sizeof (shortest_native_sorted[0]), sort_by_shortest_native_name);
+  qsort (shortest_native_sorted, nmounts, sizeof (shortest_native_sorted[0]), sort_posix_subdirs_before_parents);
+  /* Disabling my new crap. */
+  #if DISABLE_NEW_STUFF
+  for (int i = 0; i < nmounts; i++)
+  {
+      longest_posix_sorted[i] = native_sorted[i];
+      shortest_native_sorted[i] = posix_sorted[i];
+  }
+  #else
+  #if ONLY_USE_NEW_STUFF
+  for (int i = 0; i < nmounts; i++)
+  {
+      native_sorted[i] = longest_posix_sorted[i];
+      posix_sorted[i] = shortest_native_sorted[i];
+  }
+  #endif
+  #endif
+  for (int i = 0; i < nmounts; i++)
+  {
+      mount_item *mi = mount + shortest_native_sorted[i];
+      debug_printf ("shortest_native_sorted (subdirs before parents)[%d] %12s       %12s", i, mi->native_path, mi->posix_path);
+  }
+  for (int i = 0; i < nmounts; i++)
+  {
+      mount_item *mi = mount + longest_posix_sorted[i];
+      debug_printf ("longest_posix_sorted[%d] %12s       %12s", i, mi->native_path, mi->posix_path);
+  }
 }
 
 /* Add an entry to the mount table.
@@ -1477,12 +1618,9 @@ mount_info::add_item (const char *native, const char *posix,
   if (i == nmounts)
     nmounts++;
 
-  if (strcmp (posixtmp, "/usr/bin") == 0)
+  if (strcmp (posixtmp, "/bin") == 0)
     got_usr_bin = true;
 
-  if (strcmp (posixtmp, "/usr/lib") == 0)
-    got_usr_lib = true;
-
   if (posixtmp[0] == '/' && posixtmp[1] == '\0' && !(mountflags & MOUNT_CYGDRIVE))
     root_idx = i;
 
diff --git a/winsup/cygwin/msys2_path_conv.cc b/winsup/cygwin/msys2_path_conv.cc
new file mode 100644
index 0000000000..5c592919da
--- /dev/null
+++ b/winsup/cygwin/msys2_path_conv.cc
@@ -0,0 +1,643 @@
+/*
+  The MSYS2 Path conversion source code is licensed under:
+  
+  CC0 1.0 Universal
+  
+  Official translations of this legal tool are available
+  
+  CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+  LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+  ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+  INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+  REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+  PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+  THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+  HEREUNDER.
+  
+  Statement of Purpose
+  
+  The laws of most jurisdictions throughout the world automatically
+  confer exclusive Copyright and Related Rights (defined below) upon the
+  creator and subsequent owner(s) (each and all, an "owner") of an
+  original work of authorship and/or a database (each, a "Work").
+  
+  Certain owners wish to permanently relinquish those rights to a Work
+  for the purpose of contributing to a commons of creative, cultural and
+  scientific works ("Commons") that the public can reliably and without
+  fear of later claims of infringement build upon, modify, incorporate
+  in other works, reuse and redistribute as freely as possible in any
+  form whatsoever and for any purposes, including without limitation
+  commercial purposes. These owners may contribute to the Commons to
+  promote the ideal of a free culture and the further production of
+  creative, cultural and scientific works, or to gain reputation or
+  greater distribution for their Work in part through the use and
+  efforts of others.
+  
+  For these and/or other purposes and motivations, and without any
+  expectation of additional consideration or compensation, the person
+  associating CC0 with a Work (the "Affirmer"), to the extent that he or
+  she is an owner of Copyright and Related Rights in the Work,
+  voluntarily elects to apply CC0 to the Work and publicly distribute
+  the Work under its terms, with knowledge of his or her Copyright and
+  Related Rights in the Work and the meaning and intended legal effect
+  of CC0 on those rights.
+  
+  1. Copyright and Related Rights. A Work made available under CC0 may
+  be protected by copyright and related or neighboring rights
+  ("Copyright and Related Rights"). Copyright and Related Rights
+  include, but are not limited to, the following:
+  
+  the right to reproduce, adapt, distribute, perform, display,
+  communicate, and translate a Work;
+  moral rights retained by the original author(s) and/or performer(s);
+  publicity and privacy rights pertaining to a person's image or
+  likeness depicted in a Work;
+  rights protecting against unfair competition in regards to a Work,
+  subject to the limitations in paragraph 4(a), below;
+  rights protecting the extraction, dissemination, use and reuse of data
+  in a Work;
+  database rights (such as those arising under Directive 96/9/EC of the
+  European Parliament and of the Council of 11 March 1996 on the legal
+  protection of databases, and under any national implementation
+  thereof, including any amended or successor version of such
+  directive); and
+  other similar, equivalent or corresponding rights throughout the world
+  based on applicable law or treaty, and any national implementations
+  thereof.
+  
+  2. Waiver. To the greatest extent permitted by, but not in
+  contravention of, applicable law, Affirmer hereby overtly, fully,
+  permanently, irrevocably and unconditionally waives, abandons, and
+  surrenders all of Affirmer's Copyright and Related Rights and
+  associated claims and causes of action, whether now known or unknown
+  (including existing as well as future claims and causes of action), in
+  the Work (i) in all territories worldwide, (ii) for the maximum
+  duration provided by applicable law or treaty (including future time
+  extensions), (iii) in any current or future medium and for any number
+  of copies, and (iv) for any purpose whatsoever, including without
+  limitation commercial, advertising or promotional purposes (the
+  "Waiver"). Affirmer makes the Waiver for the benefit of each member of
+  the public at large and to the detriment of Affirmer's heirs and
+  successors, fully intending that such Waiver shall not be subject to
+  revocation, rescission, cancellation, termination, or any other legal
+  or equitable action to disrupt the quiet enjoyment of the Work by the
+  public as contemplated by Affirmer's express Statement of Purpose.
+  
+  3. Public License Fallback. Should any part of the Waiver for any
+  reason be judged legally invalid or ineffective under applicable law,
+  then the Waiver shall be preserved to the maximum extent permitted
+  taking into account Affirmer's express Statement of Purpose. In
+  addition, to the extent the Waiver is so judged Affirmer hereby grants
+  to each affected person a royalty-free, non transferable, non
+  sublicensable, non exclusive, irrevocable and unconditional license to
+  exercise Affirmer's Copyright and Related Rights in the Work (i) in
+  all territories worldwide, (ii) for the maximum duration provided by
+  applicable law or treaty (including future time extensions), (iii) in
+  any current or future medium and for any number of copies, and (iv)
+  for any purpose whatsoever, including without limitation commercial,
+  advertising or promotional purposes (the "License"). The License shall
+  be deemed effective as of the date CC0 was applied by Affirmer to the
+  Work. Should any part of the License for any reason be judged legally
+  invalid or ineffective under applicable law, such partial invalidity
+  or ineffectiveness shall not invalidate the remainder of the License,
+  and in such case Affirmer hereby affirms that he or she will not (i)
+  exercise any of his or her remaining Copyright and Related Rights in
+  the Work or (ii) assert any associated claims and causes of action
+  with respect to the Work, in either case contrary to Affirmer's
+  express Statement of Purpose.
+  
+  4. Limitations and Disclaimers.
+  
+  No trademark or patent rights held by Affirmer are waived, abandoned,
+  surrendered, licensed or otherwise affected by this document.
+  Affirmer offers the Work as-is and makes no representations or
+  warranties of any kind concerning the Work, express, implied,
+  statutory or otherwise, including without limitation warranties of
+  title, merchantability, fitness for a particular purpose, non
+  infringement, or the absence of latent or other defects, accuracy, or
+  the present or absence of errors, whether or not discoverable, all to
+  the greatest extent permissible under applicable law.
+  Affirmer disclaims responsibility for clearing rights of other persons
+  that may apply to the Work or any use thereof, including without
+  limitation any person's Copyright and Related Rights in the Work.
+  Further, Affirmer disclaims responsibility for obtaining any necessary
+  consents, permissions or other rights required for any use of the
+  Work.
+  Affirmer understands and acknowledges that Creative Commons is not a
+  party to this document and has no duty or obligation with respect to
+  this CC0 or use of the Work.
+
+  Contributions thanks to:
+    niXman <i.nixman@autistici.org>
+    Ely Arzhannikov <iarzhannikov@gmail.com>
+    Alexey Pavlov <alexpux@gmail.com>
+    Ray Donnelly <mingw.android@gmail.com>
+    Johannes Schindelin <johannes.schindelin@gmx.de>
+  
+*/
+
+#include "winsup.h"
+#include "miscfuncs.h"
+#include <ctype.h>
+#include <winioctl.h>
+#include <shlobj.h>
+#include <sys/param.h>
+#include <sys/cygwin.h>
+#include "cygerrno.h"
+#include "security.h"
+#include "path.h"
+#include "fhandler.h"
+#include "dtable.h"
+#include "cygheap.h"
+#include "shared_info.h"
+#include "cygtls.h"
+#include "tls_pbuf.h"
+#include "environ.h"
+#include <assert.h>
+#include <ntdll.h>
+#include <wchar.h>
+#include <wctype.h>
+
+#include "msys2_path_conv.h"
+
+typedef enum PATH_TYPE_E {
+    NONE = 0,
+    SIMPLE_WINDOWS_PATH,
+    ESCAPE_WINDOWS_PATH,
+    WINDOWS_PATH_LIST,
+    UNC,
+    ESCAPED_PATH,
+    ROOTED_PATH,
+    POSIX_PATH_LIST,
+    RELATIVE_PATH,
+    URL
+} path_type;
+
+int is_special_posix_path(const char* from, const char* to, char** dst, const char* dstend);
+void posix_to_win32_path(const char* from, const char* to, char** dst, const char* dstend);
+
+
+path_type find_path_start_and_type(const char** src, int recurse, const char* end);
+void copy_to_dst(const char* from, const char* to, char** dst, const char* dstend);
+void convert_path(const char** from, const char* to, path_type type, char** dst, const char* dstend);
+
+//Transformations
+//SIMPLE_WINDOWS_PATH converter. Copy as is. Hold C:\Something\like\this
+void swp_convert(const char** from, const char* to, char** dst, const char* dstend);
+//ESCAPE_WINDOWS_PATH converter. Turn backslashes to slashes and skip first /. Hold /C:\Somethind\like\this
+void ewp_convert(const char** from, const char* to, char** dst, const char* dstend);
+//WINDOWS_PATH_LIST converter. Copy as is. Hold /something/like/this;
+void wpl_convert(const char** from, const char* to, char** dst, const char* dstend);
+//UNC convert converter. Copy as is. Hold //somethig/like/this
+void unc_convert(const char** from, const char* to, char** dst, const char* dstend);
+//ESCAPED_PATH converter. Turn backslashes to slashes and skip first /. Hold //something\like\this
+void ep_convert(const char** from, const char* to, char** dst, const char* dstend);
+//ROOTED_PATH converter. Prepend root dir to front. Hold /something/like/this
+void rp_convert(const char** from, const char* to, char** dst, const char* dstend);
+//URL converter. Copy as is.
+void url_convert(const char** from, const char* to, char** dst, const char* dstend);
+//POSIX_PATH_LIST. Hold x::x/y:z
+void ppl_convert(const char** from, const char* to, char** dst, const char* dstend);
+
+
+void find_end_of_posix_list(const char** to, int* in_string) {
+    for (; **to != '\0' && (!in_string || **to != *in_string); ++*to) {
+    }
+
+    if (**to == *in_string) {
+        *in_string = 0;
+    }
+}
+
+void find_end_of_rooted_path(const char** from, const char** to, int* in_string) {
+    for (const char* it = *from; *it != '\0' && it != *to; ++it)
+        if (*it == '.' && *(it + 1) == '.' && *(it - 1) == '/') {
+            *to = it - 1;
+            return;
+        }
+
+    for (; **to != '\0'; ++*to) {
+        if (*in_string == 0 && **to == ' ') {
+            return;
+        }
+
+        if (**to == *in_string) {
+            *in_string = 0;
+            return;
+        }
+
+        if (**to == '/') {
+            if (*(*to - 1) == ' ') {
+                *to -= 1;
+                return;
+            }
+        }
+    }
+}
+
+void sub_convert(const char** from, const char** to, char** dst, const char* dstend, int* in_string) {
+    const char* copy_from = *from;
+    path_type type = find_path_start_and_type(from, false, *to);
+    debug_printf("found type %d for path %s", type, copy_from);
+
+    if (type == POSIX_PATH_LIST) {
+        find_end_of_posix_list(to, in_string);
+    }
+
+    if (type == ROOTED_PATH) {
+        find_end_of_rooted_path(from, to, in_string);
+    }
+
+    copy_to_dst(copy_from, *from, dst, dstend);
+
+    if (type != NONE) {
+        convert_path(from, *to, type, dst, dstend);
+    }
+
+    if (*dst != dstend) {
+        **dst = **to;
+        *dst += 1;
+    }
+}
+
+const char* convert(char *dst, size_t dstlen, const char *src) {
+    if (dst == NULL || dstlen == 0 || src == NULL) {
+        return dst;
+    }
+
+    int need_convert = false;
+    for (const char* it = src; *it != '\0'; ++it) {
+        if (*it == '\\' || *it == '/') {
+            need_convert = true;
+            break;
+        }
+        if (isspace(*it)) {
+            need_convert = false;
+            break;
+        }
+    }
+
+    char* dstit = dst;
+    char* dstend = dst + dstlen;
+    if (!need_convert) {
+        copy_to_dst(src, NULL, &dstit, dstend);
+        *dstit = '\0';
+        return dst;
+    }
+    *dstend = '\0';
+
+    const char* srcit = src;
+    const char* srcbeg = src;
+
+    int in_string = false;
+
+    for (; *srcit != '\0'; ++srcit) {
+        if (*srcit == '\'' || *srcit == '"') {
+            if (in_string == *srcit) {
+                if (*(srcit + 1) != in_string) {
+                    in_string = 0;
+                }
+            } else {
+                in_string = *srcit;
+            }
+            continue;
+        }
+    }
+
+    sub_convert(&srcbeg, &srcit, &dstit, dstend, &in_string);
+    if (!*srcit) {
+      *dstit = '\0';
+      return dst;
+    }
+    srcbeg = srcit + 1;
+    for (; *srcit != '\0'; ++srcit) {
+      continue;
+    }
+    copy_to_dst(srcbeg, srcit, &dstit, dstend);
+    *dstit = '\0';
+
+    /*if (dstit - dst < 2) {
+        dstit = dst;
+        copy_to_dst(src, NULL, &dstit, dstend);
+        *dstit = '\0';
+    }*/
+
+    return dst;
+}
+
+void copy_to_dst(const char* from, const char* to, char** dst, const char* dstend) {
+    for (; (*from != '\0') && (from != to) && (*dst != dstend); ++from, ++(*dst)) {
+        **dst = *from;
+    }
+}
+
+const char** move(const char** p, int count) {
+    *p += count;
+    return p;
+}
+
+path_type find_path_start_and_type(const char** src, int recurse, const char* end) {
+    const char* it = *src;
+
+    if (*it == '\0' || it == end) return NONE;
+
+    while (!isalnum(*it) && *it != '/' && *it != '\\' && *it != ':' && *it != '-' && *it != '.') {
+        recurse = true;
+        it = ++*src;
+        if (it == end || *it == '\0') return NONE;
+    }
+
+    path_type result = NONE;
+
+    if (it + 1 == end) {
+        switch (*it) {
+        case '/':   return ROOTED_PATH ;
+        default:    return SIMPLE_WINDOWS_PATH;
+        }
+    }
+
+    if (isalpha(*it) && *(it + 1) == ':') {
+        if (*(it + 2) == '\\') {
+            return SIMPLE_WINDOWS_PATH;
+        }
+
+        if (*(it + 2) == '/' && memchr(it + 2, ':', end - (it + 2)) == NULL) {
+            return SIMPLE_WINDOWS_PATH;
+        }
+
+        if (*(it + 2) == '/' && memchr(it + 2, ';', end - (it + 2))) {
+            return WINDOWS_PATH_LIST;
+        }
+    }
+
+    if (*it == '.' && (*(it + 1) == '.' || *(it + 1) == '/') && memchr(it + 2, ':', end - (it + 2)) == NULL) {
+        return RELATIVE_PATH;
+    }
+
+    if (*it == '/') {
+        it += 1;
+
+        if (isalpha(*it) && *(it + 1) == ':') {
+            return ESCAPE_WINDOWS_PATH;
+        }
+
+        if (*it == '.' && *(it + 1) == '.') {
+            return SIMPLE_WINDOWS_PATH;
+        }
+
+        if (*it == '/') {
+            it += 1;
+            switch(*it) {
+              case ':': return URL;
+              case '/': return ESCAPED_PATH;
+            }
+            if (memchr(it, '/', end - it))
+              return UNC;
+            else
+              return ESCAPED_PATH;
+        }
+
+        for (; *it != '\0' && it != end; ++it) {
+            switch(*it) {
+                case ':': {char ch = *(it + 1); if (ch == '/' || ch == ':' || ch == '.') return POSIX_PATH_LIST;} return WINDOWS_PATH_LIST;
+                case ';': return WINDOWS_PATH_LIST;
+            }
+        }
+
+        if (result != NONE) {
+            return result;
+        }
+
+        return ROOTED_PATH;
+    }
+
+    int starts_with_minus = 0;
+    int starts_with_minus_alpha = 0;
+    if (*it == '-') {
+      starts_with_minus = 1;
+      it += 1;
+      if (isalpha(*it)) {
+        it += 1;
+        starts_with_minus_alpha = 1;
+        if (memchr(it, ';', end - it)) {
+        	return WINDOWS_PATH_LIST;
+        }
+      }
+    }
+
+    for (const char* it2 = it; *it2 != '\0' && it2 != end; ++it2) {
+        char ch = *it2;
+        if (starts_with_minus_alpha) {
+            if (isalpha(ch) && (*(it2+1) == ':') && (*(it2+2) == '/')) {
+                return SIMPLE_WINDOWS_PATH;
+            }
+            if (ch == '/'&& memchr(it2, ',', end - it2) == NULL) {
+                *src = it2;
+                return find_path_start_and_type(src, true, end);
+            }
+            starts_with_minus_alpha = 0;
+        }
+        if (ch == '\'' || ch == '"')
+            starts_with_minus = false;
+        if ((ch == '=') || (ch == ':' && starts_with_minus) || ((ch == '\'' || ch == '"') && result == NONE)) {
+            *src = it2 + 1;
+            return find_path_start_and_type(src, true, end);
+        }
+
+        if (ch == ',' && starts_with_minus) {
+            *src = it2 + 1;
+            return find_path_start_and_type(src, true, end);
+        }
+
+        if (ch == ':' && it2 + 1 != end) {
+            it2 += 1;
+            ch = *it2;
+            if (ch == '/' || ch == ':' || ch == '.') {
+                if (ch == '/' && *(it2 + 1) == '/') {
+                    return URL;
+                } else {
+                    return POSIX_PATH_LIST;
+                }
+            } else if (memchr(it2, '=', end - it2) == NULL) {
+                return SIMPLE_WINDOWS_PATH;
+            }
+        }
+    }
+
+    if (result != NONE) {
+        *src = it;
+        return result;
+    }
+
+    return SIMPLE_WINDOWS_PATH;
+}
+
+void convert_path(const char** from, const char* to, path_type type, char** dst, const char* dstend) {
+    switch(type) {
+        case SIMPLE_WINDOWS_PATH: swp_convert(from, to, dst, dstend); break;
+        case ESCAPE_WINDOWS_PATH: ewp_convert(from, to, dst, dstend); break;
+        case WINDOWS_PATH_LIST: wpl_convert(from, to, dst, dstend); break;
+        case RELATIVE_PATH: swp_convert(from, to, dst, dstend); break;
+        case UNC: unc_convert(from, to, dst, dstend); break;
+        case ESCAPED_PATH: ep_convert(from, to, dst, dstend); break;
+        case ROOTED_PATH: rp_convert(from, to, dst, dstend); break;
+        case URL: url_convert(from, to, dst, dstend); break;
+        case POSIX_PATH_LIST: ppl_convert(from, to, dst, dstend); break;
+        case NONE: // prevent warnings;
+        default:
+                return;
+    }
+}
+
+void swp_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    copy_to_dst(*from, to, dst, dstend);
+}
+
+void ewp_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    *from += 1;
+    unc_convert(from, to, dst, dstend);
+}
+
+void wpl_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    swp_convert(from, to, dst, dstend);
+}
+
+void unc_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    const char* it = *from;
+    for (; (*it != '\0' && it != to) && (*dst != dstend); ++it, ++(*dst)) {
+        if (*it == '\\') {
+            **dst = '/';
+        } else {
+            **dst = *it;
+        }
+    }
+}
+
+void ep_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    ewp_convert(from, to, dst, dstend);
+}
+
+void rp_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    const char* it = *from;
+    const char* real_to = to;
+
+    if (*real_to == '\0')  {
+        real_to -= 1;
+        if (*real_to != '\'' && *real_to != '"') {
+            real_to += 1;
+        }
+    }
+
+    if (!is_special_posix_path(*from, real_to, dst, dstend)) {
+        posix_to_win32_path(it, real_to, dst, dstend);
+    }
+
+    if (*dst != dstend && real_to != to) {
+        **dst = *real_to;
+        *dst += 1;
+    }
+}
+
+void url_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    unc_convert(from, to, dst, dstend);
+}
+
+void subp_convert(const char** from, const char* end, int is_url, char** dst, const char* dstend) {
+    const char* begin = *from;
+    path_type type = is_url ? URL : find_path_start_and_type(from, 0, end);
+    copy_to_dst(begin, *from, dst, dstend);
+
+    if (type == NONE) {
+        return;
+    }
+
+    char* start = *dst;
+    convert_path(from, end, type, dst, dstend);
+
+    if (!is_url) {
+        for (; start != *dst; ++start) {
+            if (*start == '/') {
+                *start = '\\';
+            }
+        }
+    }
+}
+
+void ppl_convert(const char** from, const char* to, char** dst, const char* dstend) {
+    const char *orig_dst = *dst;
+    const char* it = *from;
+    const char* beg = it;
+    int prev_was_simc = 0;
+    int is_url = 0;
+    for (; (*it != '\0' && it != to) && (*dst != dstend); ++it) {
+        if (*it == ':') {
+            if (prev_was_simc) {
+                continue;
+            }
+            if (*(it + 1) == '/' && *(it + 2) == '/' && isalpha(*beg)) {
+                is_url = 1;
+                /* double-check: protocol must be alnum (or +) */
+                for (const char *p = beg; p != it; ++p)
+                    if (!isalnum(*p) && *p != '+') {
+                        is_url = 0;
+                        break;
+                    }
+                if (is_url)
+                    continue;
+            }
+            prev_was_simc = 1;
+            subp_convert(&beg, it, is_url, dst, dstend);
+            is_url = 0;
+
+            if (*dst == dstend) {
+                system_printf("Path cut off during conversion: %s\n", orig_dst);
+                break;
+            }
+
+            **dst = ';';
+            *dst += 1;
+        }
+
+        if (*it != ':' && prev_was_simc) {
+            prev_was_simc = 0;
+            beg = it;
+        }
+    }
+
+    if (!prev_was_simc) {
+        subp_convert(&beg, it, is_url, dst, dstend);
+    }
+}
+
+int is_special_posix_path(const char* from, const char* to, char** dst, const char* dstend) {
+    const char dev_null[] = "/dev/null";
+
+    if ((to - from) == (sizeof(dev_null) - 1) && strncmp(from, "/dev/null", to - from) == 0) {
+        copy_to_dst("nul", NULL, dst, dstend);
+        return true;
+    }
+    return false;
+}
+
+void posix_to_win32_path(const char* from, const char* to, char** dst, const char* dstend) {
+    if ( from != to ) {
+        tmp_pathbuf tp;
+        char *one_path = tp.c_get();
+        strncpy(one_path, from, to-from);
+        one_path[to-from] = '\0';
+
+        path_conv conv (one_path, PC_NOFULL);
+        if (conv.error)
+        {
+          set_errno(conv.error);
+          copy_to_dst(one_path, NULL, dst, dstend);
+        } else {
+          char* win32_path = tp.c_get();
+          stpcpy (win32_path, conv.get_win32 ());
+          for (; (*win32_path != '\0') && (*dst != dstend); ++win32_path, ++(*dst)) {
+             **dst = (*win32_path == '\\') ? '/' : *win32_path;
+          }
+        }
+    }
+}
+
diff --git a/winsup/cygwin/msys2_path_conv.h b/winsup/cygwin/msys2_path_conv.h
new file mode 100644
index 0000000000..67d85ecb64
--- /dev/null
+++ b/winsup/cygwin/msys2_path_conv.h
@@ -0,0 +1,147 @@
+/*
+  The MSYS2 Path conversion source code is licensed under:
+  
+  CC0 1.0 Universal
+  
+  Official translations of this legal tool are available
+  
+  CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+  LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+  ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+  INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+  REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+  PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+  THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+  HEREUNDER.
+  
+  Statement of Purpose
+  
+  The laws of most jurisdictions throughout the world automatically
+  confer exclusive Copyright and Related Rights (defined below) upon the
+  creator and subsequent owner(s) (each and all, an "owner") of an
+  original work of authorship and/or a database (each, a "Work").
+  
+  Certain owners wish to permanently relinquish those rights to a Work
+  for the purpose of contributing to a commons of creative, cultural and
+  scientific works ("Commons") that the public can reliably and without
+  fear of later claims of infringement build upon, modify, incorporate
+  in other works, reuse and redistribute as freely as possible in any
+  form whatsoever and for any purposes, including without limitation
+  commercial purposes. These owners may contribute to the Commons to
+  promote the ideal of a free culture and the further production of
+  creative, cultural and scientific works, or to gain reputation or
+  greater distribution for their Work in part through the use and
+  efforts of others.
+  
+  For these and/or other purposes and motivations, and without any
+  expectation of additional consideration or compensation, the person
+  associating CC0 with a Work (the "Affirmer"), to the extent that he or
+  she is an owner of Copyright and Related Rights in the Work,
+  voluntarily elects to apply CC0 to the Work and publicly distribute
+  the Work under its terms, with knowledge of his or her Copyright and
+  Related Rights in the Work and the meaning and intended legal effect
+  of CC0 on those rights.
+  
+  1. Copyright and Related Rights. A Work made available under CC0 may
+  be protected by copyright and related or neighboring rights
+  ("Copyright and Related Rights"). Copyright and Related Rights
+  include, but are not limited to, the following:
+  
+  the right to reproduce, adapt, distribute, perform, display,
+  communicate, and translate a Work;
+  moral rights retained by the original author(s) and/or performer(s);
+  publicity and privacy rights pertaining to a person's image or
+  likeness depicted in a Work;
+  rights protecting against unfair competition in regards to a Work,
+  subject to the limitations in paragraph 4(a), below;
+  rights protecting the extraction, dissemination, use and reuse of data
+  in a Work;
+  database rights (such as those arising under Directive 96/9/EC of the
+  European Parliament and of the Council of 11 March 1996 on the legal
+  protection of databases, and under any national implementation
+  thereof, including any amended or successor version of such
+  directive); and
+  other similar, equivalent or corresponding rights throughout the world
+  based on applicable law or treaty, and any national implementations
+  thereof.
+  
+  2. Waiver. To the greatest extent permitted by, but not in
+  contravention of, applicable law, Affirmer hereby overtly, fully,
+  permanently, irrevocably and unconditionally waives, abandons, and
+  surrenders all of Affirmer's Copyright and Related Rights and
+  associated claims and causes of action, whether now known or unknown
+  (including existing as well as future claims and causes of action), in
+  the Work (i) in all territories worldwide, (ii) for the maximum
+  duration provided by applicable law or treaty (including future time
+  extensions), (iii) in any current or future medium and for any number
+  of copies, and (iv) for any purpose whatsoever, including without
+  limitation commercial, advertising or promotional purposes (the
+  "Waiver"). Affirmer makes the Waiver for the benefit of each member of
+  the public at large and to the detriment of Affirmer's heirs and
+  successors, fully intending that such Waiver shall not be subject to
+  revocation, rescission, cancellation, termination, or any other legal
+  or equitable action to disrupt the quiet enjoyment of the Work by the
+  public as contemplated by Affirmer's express Statement of Purpose.
+  
+  3. Public License Fallback. Should any part of the Waiver for any
+  reason be judged legally invalid or ineffective under applicable law,
+  then the Waiver shall be preserved to the maximum extent permitted
+  taking into account Affirmer's express Statement of Purpose. In
+  addition, to the extent the Waiver is so judged Affirmer hereby grants
+  to each affected person a royalty-free, non transferable, non
+  sublicensable, non exclusive, irrevocable and unconditional license to
+  exercise Affirmer's Copyright and Related Rights in the Work (i) in
+  all territories worldwide, (ii) for the maximum duration provided by
+  applicable law or treaty (including future time extensions), (iii) in
+  any current or future medium and for any number of copies, and (iv)
+  for any purpose whatsoever, including without limitation commercial,
+  advertising or promotional purposes (the "License"). The License shall
+  be deemed effective as of the date CC0 was applied by Affirmer to the
+  Work. Should any part of the License for any reason be judged legally
+  invalid or ineffective under applicable law, such partial invalidity
+  or ineffectiveness shall not invalidate the remainder of the License,
+  and in such case Affirmer hereby affirms that he or she will not (i)
+  exercise any of his or her remaining Copyright and Related Rights in
+  the Work or (ii) assert any associated claims and causes of action
+  with respect to the Work, in either case contrary to Affirmer's
+  express Statement of Purpose.
+  
+  4. Limitations and Disclaimers.
+  
+  No trademark or patent rights held by Affirmer are waived, abandoned,
+  surrendered, licensed or otherwise affected by this document.
+  Affirmer offers the Work as-is and makes no representations or
+  warranties of any kind concerning the Work, express, implied,
+  statutory or otherwise, including without limitation warranties of
+  title, merchantability, fitness for a particular purpose, non
+  infringement, or the absence of latent or other defects, accuracy, or
+  the present or absence of errors, whether or not discoverable, all to
+  the greatest extent permissible under applicable law.
+  Affirmer disclaims responsibility for clearing rights of other persons
+  that may apply to the Work or any use thereof, including without
+  limitation any person's Copyright and Related Rights in the Work.
+  Further, Affirmer disclaims responsibility for obtaining any necessary
+  consents, permissions or other rights required for any use of the
+  Work.
+  Affirmer understands and acknowledges that Creative Commons is not a
+  party to this document and has no duty or obligation with respect to
+  this CC0 or use of the Work.
+
+  Contributions thanks to:
+    niXman <i.nixman@autistici.org>
+    Ely Arzhannikov <iarzhannikov@gmail.com>
+    Alexey Pavlov <alexpux@gmail.com>
+    Ray Donnelly <mingw.android@gmail.com>
+    Johannes Schindelin <johannes.schindelin@gmx.de>
+  
+*/
+
+#ifndef PATH_CONV_H_DB4IQBH3
+#define PATH_CONV_H_DB4IQBH3
+
+#include <stdlib.h>
+
+const char* convert(char *dst, size_t dstlen, const char *src);
+
+#endif /* end of include guard: PATH_CONV_H_DB4IQBH3 */
+
diff --git a/winsup/cygwin/path.cc b/winsup/cygwin/path.cc
index 5ad9e201f7..af88ecfcf9 100644
--- a/winsup/cygwin/path.cc
+++ b/winsup/cygwin/path.cc
@@ -66,6 +66,7 @@
 #include "shared_info.h"
 #include "tls_pbuf.h"
 #include "environ.h"
+#include "msys2_path_conv.h"
 #undef basename
 
 suffix_info stat_suffixes[] =
@@ -708,6 +709,12 @@ path_conv::check (const char *src, unsigned opt,
 	      need_directory = 1;
 	      *--tail = '\0';
 	    }
+	  /* Special case for "/" must set need_directory, without removing
+	     trailing slash */
+	  else if (tail == path_copy + 1 && isslash (tail[-1]))
+	    {
+	      need_directory = 1;
+	    }
 	  path_end = tail;
 
 	  /* Scan path_copy from right to left looking either for a symlink
@@ -1247,6 +1254,7 @@ path_conv::check (const char *src, unsigned opt,
 		cfree (wide_path);
 	      wide_path = NULL;
 	    }
+
 	  if (need_directory)
 	    {
 	      size_t n = strlen (this->path);
@@ -1681,6 +1689,89 @@ conv_path_list (const char *src, char *dst, size_t size,
 
 /********************** Symbolic Link Support **************************/
 
+/*
+  Create a deep copy of src as dst, while avoiding descending in origpath.
+*/
+static int
+recursiveCopy (char * src, char * dst, const char * origpath)
+{
+  WIN32_FIND_DATA dHfile;
+  HANDLE dH = INVALID_HANDLE_VALUE;
+  BOOL findfiles;
+  int srcpos = strlen (src);
+  int dstpos = strlen (dst);
+  int res = -1;
+
+  debug_printf("recursiveCopy (%s, %s)", src, dst);
+
+  /* Create the destination directory */
+  if (!CreateDirectoryEx (src, dst, NULL))
+    {
+      debug_printf("CreateDirectoryEx(%s, %s, 0) failed", src, dst);
+      __seterrno ();
+      goto done;
+    }
+  /* Descend into the source directory */
+  if (srcpos + 2 >= MAX_PATH || dstpos + 1 >= MAX_PATH)
+    {
+      set_errno (ENAMETOOLONG);
+      goto done;
+    }
+  strcat (src, "\\*");
+  strcat (dst, "\\");
+  dH = FindFirstFile (src, &dHfile);
+  debug_printf("dHfile(1): %s", dHfile.cFileName);
+  findfiles = FindNextFile (dH, &dHfile);
+  debug_printf("dHfile(2): %s", dHfile.cFileName);
+  findfiles = FindNextFile (dH, &dHfile);
+  while (findfiles)
+    {
+      /* Append the directory item filename to both source and destination */
+      int filelen = strlen (dHfile.cFileName);
+      debug_printf("dHfile(3): %s", dHfile.cFileName);
+      if (srcpos + 1 + filelen >= MAX_PATH ||
+          dstpos + 1 + filelen >= MAX_PATH)
+        {
+          set_errno (ENAMETOOLONG);
+          goto done;
+        }
+      strcpy (&src[srcpos+1], dHfile.cFileName);
+      strcpy (&dst[dstpos+1], dHfile.cFileName);
+      debug_printf("%s -> %s", src, dst);
+      if (dHfile.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+        {
+          /* Recurse into the child directory */
+          debug_printf("%s <-> %s", src, origpath);
+          if (strcmp (src, origpath)) // avoids endless recursion
+            if (recursiveCopy (src, dst, origpath))
+              goto done;
+        }
+      else
+        {
+          /* Just copy the file */
+          if (!CopyFile (src, dst, FALSE))
+            {
+              __seterrno ();
+              goto done;
+            }
+        }
+      findfiles = FindNextFile (dH, &dHfile);
+    }
+  if (GetLastError() != ERROR_NO_MORE_FILES)
+    {
+      __seterrno ();
+      goto done;
+    }
+  res = 0;
+
+done:
+
+  if (dH != INVALID_HANDLE_VALUE)
+    FindClose (dH);
+
+  return res;
+}
+
 /* Create a symlink from FROMPATH to TOPATH. */
 
 extern "C" int
@@ -2218,6 +2309,77 @@ symlink_worker (const char *oldpath, path_conv &win32_newpath, bool isdevice)
 	}
       else /* wsym_type == WSYM_sysfile */
 	{
+          if (wsym_type == WSYM_deepcopy)
+	    {
+	      path_conv src_path;
+	      src_path.check (oldpath, PC_SYM_NOFOLLOW, stat_suffixes);
+	      if (src_path.error)
+		{
+		  set_errno (src_path.error);
+		  __leave;
+		}
+	      if (!src_path.isdevice () && !src_path.is_fs_special ())
+	        {
+		  /* MSYS copy file instead make symlink */
+
+		  char * real_oldpath;
+		  if (isabspath (oldpath))
+		    strcpy (real_oldpath = tp.c_get (), oldpath);
+		  else
+		    /* Find the real source path, relative
+		       to the directory of the destination */
+		    {
+		      /* Determine the character position of the last path component */
+		      const char *newpath = win32_newpath.get_posix();
+		      int pos = strlen (newpath);
+		      while (--pos >= 0)
+			if (isdirsep (newpath[pos]))
+			  break;
+		      /* Append the source path to the directory
+			 component of the destination */
+		      if (pos+1+strlen(oldpath) >= MAX_PATH)
+			{
+			  set_errno(ENAMETOOLONG);
+			  __leave;
+			}
+		      strcpy (real_oldpath = tp.c_get (), newpath);
+		      strcpy (&real_oldpath[pos+1], oldpath);
+		    }
+
+		  /* As a MSYS limitation, the source path must exist. */
+		  path_conv win32_oldpath;
+		  win32_oldpath.check (real_oldpath, PC_SYM_NOFOLLOW, stat_suffixes);
+		  if (!win32_oldpath.exists ())
+		    {
+		      set_errno (ENOENT);
+		      __leave;
+		    }
+
+		  char *w_newpath;
+		  char *w_oldpath;
+		  stpcpy (w_newpath = tp.c_get (), win32_newpath.get_win32());
+		  stpcpy (w_oldpath = tp.c_get (), win32_oldpath.get_win32());
+		  if (win32_oldpath.isdir())
+		    {
+		      char *origpath;
+		      strcpy (origpath = tp.c_get (), w_oldpath);
+		      res = recursiveCopy (w_oldpath, w_newpath, origpath);
+		    }
+		  else
+		    {
+		      if (!CopyFile (w_oldpath, w_newpath, FALSE))
+			{
+			  __seterrno ();
+			}
+		      else
+			{
+			  res = 0;
+			}
+		    }
+		  __leave;
+		}
+	    }
+
 	  /* Default technique creating a symlink. */
 	  buf = tp.t_get ();
 	  cp = stpcpy (buf, SYMLINK_COOKIE);
@@ -3528,7 +3690,8 @@ symlink_info::check (char *path, const suffix_info *suffixes, fs_info &fs,
 	 differ, return the final path as symlink content and set symlen
 	 to a negative value.  This forces path_conv::check to restart
 	 symlink evaluation with the new path. */
-      if ((pc_flags & (PC_SYM_FOLLOW | PC_SYM_NOFOLLOW_REP)) == PC_SYM_FOLLOW)
+      if (nativeinnerlinks
+	  && (pc_flags & (PC_SYM_FOLLOW | PC_SYM_NOFOLLOW_REP)) == PC_SYM_FOLLOW)
 	{
 	  PWCHAR fpbuf = tp.w_get ();
 	  DWORD ret;
@@ -3838,6 +4001,73 @@ fchdir (int fd)
   return res;
 }
 
+//
+// Important: If returned pointer == arg, then this function
+//            did not malloc that pointer; otherwise free it.
+//
+extern "C" char *
+arg_heuristic_with_exclusions (char const * const arg, char const * exclusions, size_t exclusions_count)
+{
+  char *arg_result;
+
+  // Must return something ..
+  size_t arglen = (arg ? strlen (arg): 0);
+  
+  if (arglen == 0 || !arg)
+  {
+    arg_result = (char *)malloc (sizeof (char));
+    arg_result[0] = '\0';
+    return arg_result;
+  }
+
+  for (size_t excl = 0; excl < exclusions_count; ++excl)
+    {
+      /* Since we've got regex linked we should maybe switch to that, but
+         running regexes for every argument could be too slow. */
+      if ( strcmp (exclusions, "*") == 0 || (strlen (exclusions) && strstr (arg, exclusions) == arg) )
+        return (char*)arg;
+      exclusions += strlen (exclusions) + 1;
+    }
+
+  // Leave enough room for at least 16 path elements; we might be converting
+  // a path list.
+  size_t stack_len = arglen + 16 * MAX_PATH;
+  char * stack_path = (char *)malloc (stack_len);
+  if (!stack_path)
+    {
+      debug_printf ("out of stack space?");
+      return (char *)arg;
+    }
+  memset (stack_path, 0, MAX_PATH);
+  convert (stack_path, stack_len - 1, arg);
+  debug_printf ("convert()'ed: %s (length %d)\n.....->: %s", arg, arglen, stack_path);
+  // Don't allocate memory if no conversion happened.
+  if (!strcmp (arg, stack_path))
+    {
+      if (arg != stack_path)
+        {
+          free (stack_path);
+        }
+      return ((char *)arg);
+    }
+  arg_result = (char *)realloc (stack_path, strlen (stack_path)+1);
+  // Windows doesn't like empty entries in PATH env. variables (;;)
+  char* semisemi = strstr(arg_result, ";;");
+  while (semisemi)
+    {
+      memmove(semisemi, semisemi+1, strlen(semisemi));
+      semisemi = strstr(semisemi, ";;");
+    }
+  return arg_result;
+}
+
+extern "C" char *
+arg_heuristic (char const * const arg)
+{
+  return arg_heuristic_with_exclusions (arg, NULL, 0);
+}
+
+
 /******************** Exported Path Routines *********************/
 
 /* Cover functions to the path conversion routines.
diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index 8dc46eead7..753d415d78 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -194,7 +194,7 @@ pinfo::maybe_set_exit_code_from_windows ()
       GetExitCodeProcess (hProcess, &x);
       set_exit_code (x);
     }
-  sigproc_printf ("pid %d, exit value - old %y, windows %y, cygwin %y",
+  sigproc_printf ("pid %d, exit value - old %y, windows %y, MSYS %y",
 		  self->pid, oexitcode, x, self->exitcode);
 }
 
diff --git a/winsup/cygwin/pseudo-reloc.cc b/winsup/cygwin/pseudo-reloc.cc
index 5a0eab936b..895cacd7b0 100644
--- a/winsup/cygwin/pseudo-reloc.cc
+++ b/winsup/cygwin/pseudo-reloc.cc
@@ -85,7 +85,7 @@ __report_error (const char *msg, ...)
   char buf[128];
   char *posix_module = NULL;
   static const char UNKNOWN_MODULE[] = "<unknown module>: ";
-  static const char CYGWIN_FAILURE_MSG[] = "Cygwin runtime failure: ";
+  static const char CYGWIN_FAILURE_MSG[] = "MSYS runtime failure: ";
   HANDLE errh = GetStdHandle (STD_ERROR_HANDLE);
   va_list args;
 
diff --git a/winsup/cygwin/scripts/mkvers.sh b/winsup/cygwin/scripts/mkvers.sh
index 96af936ec2..98826f8fc9 100755
--- a/winsup/cygwin/scripts/mkvers.sh
+++ b/winsup/cygwin/scripts/mkvers.sh
@@ -123,7 +123,7 @@ dir=$(echo $dir | sed -e 's%/include/cygwin.*$%%' -e 's%include/cygwin.*$%.%')
 ) | while read var; do
     read val
 cat <<EOF
-  "%%% Cygwin $var: $val\n"
+  "%%% MSYS $var: $val\n"
 EOF
 done | tee /tmp/mkvers.$$ 1>&9
 
@@ -135,9 +135,9 @@ trap "rm -f /tmp/mkvers.$$" 0 1 2 15
 #
 cat <<EOF 1>&9
 #ifdef DEBUGGING
-  "%%% Cygwin shared id: " CYGWIN_VERSION_DLL_IDENTIFIER "S" shared_data_version "-$builddate\n"
+  "%%% MSYS shared id: " CYGWIN_VERSION_DLL_IDENTIFIER "S" shared_data_version "-$builddate\n"
 #else
-  "%%% Cygwin shared id: " CYGWIN_VERSION_DLL_IDENTIFIER "S" shared_data_version "\n"
+  "%%% MSYS shared id: " CYGWIN_VERSION_DLL_IDENTIFIER "S" shared_data_version "\n"
 #endif
   "END_CYGWIN_VERSION_INFO\n\0";
 cygwin_version_info cygwin_version =
diff --git a/winsup/cygwin/scripts/speclib b/winsup/cygwin/scripts/speclib
index e6d4d8e948..4dcadcbfac 100755
--- a/winsup/cygwin/scripts/speclib
+++ b/winsup/cygwin/scripts/speclib
@@ -38,6 +38,7 @@ while (<$nm_fd>) {
     study;
     if (/ I _?(.*)_dll_iname/o) {
 	$dllname = $1;
+	$dllname =~ s/_2_0/-2.0/;
     } else {
 	my ($file, $member, $symbol) = m%^([^:]*):([^:]*(?=:))?.* T (.*)%o;
 	next if !defined($symbol) || $symbol =~ $exclude_regex;
diff --git a/winsup/cygwin/sec/auth.cc b/winsup/cygwin/sec/auth.cc
index 43b5803893..db1d5c8977 100644
--- a/winsup/cygwin/sec/auth.cc
+++ b/winsup/cygwin/sec/auth.cc
@@ -462,7 +462,7 @@ verify_token (HANDLE token, cygsid &usersid, user_groups &groups, bool *pintern)
       if (!NT_SUCCESS (status))
 	debug_printf ("NtQueryInformationToken(), %y", status);
       else
-	*pintern = intern = !memcmp (ts.SourceName, "Cygwin.1", 8);
+	*pintern = intern = !memcmp (ts.SourceName, "MSYS.2", 6);
     }
   /* Verify usersid */
   cygsid tok_usersid (NO_SID);
@@ -747,7 +747,7 @@ s4uauth (bool logon, PCWSTR domain, PCWSTR user, NTSTATUS &ret_status)
     {
       /* Register as logon process. */
       debug_printf ("Impersonation requested");
-      RtlInitAnsiString (&name, "Cygwin");
+      RtlInitAnsiString (&name, "MSYS");
       status = LsaRegisterLogonProcess (&name, &lsa_hdl, &sec_mode);
     }
   else
@@ -786,11 +786,11 @@ s4uauth (bool logon, PCWSTR domain, PCWSTR user, NTSTATUS &ret_status)
     }
 
   /* Create origin. */
-  stpcpy (origin.buf, "Cygwin");
+  stpcpy (origin.buf, "MSYS");
   RtlInitAnsiString (&origin.str, origin.buf);
 
   /* Create token source. */
-  memcpy (ts.SourceName, "Cygwin.1", 8);
+  memcpy (ts.SourceName, "MSYS.2", 6);
   ts.SourceIdentifier.HighPart = 0;
   ts.SourceIdentifier.LowPart = kerberos_auth ? 0x0105 : 0x0106;
 
diff --git a/winsup/cygwin/spawn.cc b/winsup/cygwin/spawn.cc
index 5ac90808ca..383f5e56fe 100644
--- a/winsup/cygwin/spawn.cc
+++ b/winsup/cygwin/spawn.cc
@@ -50,7 +50,7 @@ perhaps_suffix (const char *prog, path_conv& buf, int& err, unsigned opt)
 
   err = 0;
   debug_printf ("prog '%s'", prog);
-  buf.check (prog, PC_SYM_FOLLOW | PC_NULLEMPTY | PC_POSIX,
+  buf.check (prog, PC_SYM_FOLLOW | PC_SYM_NOFOLLOW_REP | PC_NULLEMPTY | PC_POSIX,
 	     (opt & FE_DLL) ? stat_suffixes : exe_suffixes);
 
   if (buf.isdir ())
@@ -281,6 +281,19 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
   bool rc;
   int res = -1;
 
+  /* Environment variable MSYS2_ARG_CONV_EXCL contains a list
+     of ';' separated argument prefixes to pass un-modified.
+     A value of * means don't convert any arguments. */
+  char* msys2_arg_conv_excl_env = getenv("MSYS2_ARG_CONV_EXCL");
+  char* msys2_arg_conv_excl = NULL;
+  size_t msys2_arg_conv_excl_count = 0;
+  if (msys2_arg_conv_excl_env)
+    {
+      msys2_arg_conv_excl = (char*)alloca (strlen(msys2_arg_conv_excl_env)+1);
+      strcpy (msys2_arg_conv_excl, msys2_arg_conv_excl_env);
+      msys2_arg_conv_excl_count = string_split_delimited (msys2_arg_conv_excl, ';');
+    }
+
   /* Check if we have been called from exec{lv}p or spawn{lv}p and mask
      mode to keep only the spawn mode. */
   bool p_type_exec = !!(mode & _P_PATH_TYPE_EXEC);
@@ -372,6 +385,20 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
 	  moreinfo->argc = newargv.argc;
 	  moreinfo->argv = newargv;
 	}
+      else
+	{
+	  for (int i = 0; i < newargv.argc; i++)
+	    {
+	      //convert argv to win32
+	      int newargvlen = strlen (newargv[i]);
+	      char *tmpbuf = (char *)malloc (newargvlen + 1);
+	      memcpy (tmpbuf, newargv[i], newargvlen + 1);
+	      tmpbuf = arg_heuristic_with_exclusions(tmpbuf, msys2_arg_conv_excl, msys2_arg_conv_excl_count);
+	      debug_printf("newargv[%d] = %s", i, newargv[i]);
+	      newargv.replace (i, tmpbuf);
+	      free (tmpbuf);
+	    }
+	}
       if ((wincmdln || !real_path.iscygexec ())
 	   && !cmd.fromargv (newargv, real_path.get_win32 (),
 			     real_path.iscygexec ()))
@@ -402,7 +429,7 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
 	 get the default error mode instead of inheriting the mode Cygwin
 	 uses.  This allows things like Windows Error Reporting/JIT debugging
 	 to work with processes launched from a Cygwin shell. */
-      if (!real_path.iscygexec ())
+      if (winjitdebug && !real_path.iscygexec ())
 	c_flags |= CREATE_DEFAULT_ERROR_MODE;
 
       /* We're adding the CREATE_BREAKAWAY_FROM_JOB flag here to workaround
@@ -499,10 +526,13 @@ child_info_spawn::worker (const char *prog_arg, const char *const *argv,
       bool switch_user = ::cygheap->user.issetuid ()
 			 && (::cygheap->user.saved_uid
 			     != ::cygheap->user.real_uid);
+      bool keep_posix = (iscmd (argv[0], "strace.exe")
+			|| iscmd (argv[0], "strace")) ? true : real_path.iscygexec ();
       moreinfo->envp = build_env (envp, envblock, moreinfo->envc,
 				  real_path.iscygexec (),
 				  switch_user ? ::cygheap->user.primary_token ()
-					      : NULL);
+					      : NULL,
+				  keep_posix);
       if (!moreinfo->envp || !envblock)
 	{
 	  set_errno (E2BIG);
diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc
index bc323235a7..725def4d27 100644
--- a/winsup/cygwin/syscalls.cc
+++ b/winsup/cygwin/syscalls.cc
@@ -297,7 +297,7 @@ try_to_bin (path_conv &pc, HANDLE &fh, ACCESS_MASK access, ULONG flags)
     }
   else
     {
-      /* Create unique filename.  Start with a dot, followed by "cyg"
+      /* Create unique filename.  Start with a dot, followed by "msys"
 	 transposed into the Unicode low surrogate area (U+dc00) on file
 	 systems supporting Unicode (except Samba), followed by the inode
 	 number in hex, followed by a path hash in hex.  The combination
@@ -305,7 +305,7 @@ try_to_bin (path_conv &pc, HANDLE &fh, ACCESS_MASK access, ULONG flags)
       RtlAppendUnicodeToString (&recycler,
 				(pc.fs_flags () & FILE_UNICODE_ON_DISK
 				 && !pc.fs_is_samba ())
-				? L".\xdc63\xdc79\xdc67" : L".cyg");
+				? L".\xdc6d\xdc73\xdc79\xdc73" : L".msys");
       pfii = (PFILE_INTERNAL_INFORMATION) infobuf;
       status = NtQueryInformationFile (fh, &io, pfii, sizeof *pfii,
 				       FileInternalInformation);
@@ -4342,7 +4342,7 @@ popen (const char *command, const char *in_type)
       fcntl (stdchild, F_SETFD, stdchild_state | FD_CLOEXEC);
 
       /* Start a shell process to run the given command without forking. */
-      pid_t pid = ch_spawn.worker ("/bin/sh", argv, environ, _P_NOWAIT,
+      pid_t pid = ch_spawn.worker ("/usr/bin/sh", argv, environ, _P_NOWAIT,
 				   __std[0], __std[1]);
 
       /* Reinstate the close-on-exec state */
diff --git a/winsup/cygwin/syslog.cc b/winsup/cygwin/syslog.cc
index 6a295501f1..431f9d2396 100644
--- a/winsup/cygwin/syslog.cc
+++ b/winsup/cygwin/syslog.cc
@@ -26,7 +26,11 @@ details. */
 #include "cygtls.h"
 #include "tls_pbuf.h"
 
+#ifdef __MSYS__
+#define CYGWIN_LOG_NAME L"MSYS"
+#else
 #define CYGWIN_LOG_NAME L"Cygwin"
+#endif
 
 static struct
 {
diff --git a/winsup/cygwin/uinfo.cc b/winsup/cygwin/uinfo.cc
index 6df8c7bbbb..9bbcf1c17f 100644
--- a/winsup/cygwin/uinfo.cc
+++ b/winsup/cygwin/uinfo.cc
@@ -2678,7 +2678,7 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap)
 		     dom, name,
 		     sid.string ((char *) sidstr),
 		     home ?: "/home/", home ? L"" : name,
-		     shell ?: "/bin/bash");
+		     shell ?: "/usr/bin/bash");
   if (gecos)
     free (gecos);
   if (home)
diff --git a/winsup/cygwin/uname.cc b/winsup/cygwin/uname.cc
index dd4160189c..a4ac0e304d 100644
--- a/winsup/cygwin/uname.cc
+++ b/winsup/cygwin/uname.cc
@@ -24,6 +24,24 @@ extern "C" int getdomainname (char *__name, size_t __len);
 #define ATTRIBUTE_NONSTRING
 #endif
 
+static const char*
+get_sysname()
+{
+#ifdef __MSYS__
+  char* msystem = getenv("MSYSTEM");
+  if (!msystem || strcmp(msystem, "MSYS") == 0)
+    return "MSYS";
+  else if (strcmp(msystem, "CYGWIN") == 0)
+    return "CYGWIN";
+  else if (strstr(msystem, "32") != NULL)
+    return "MINGW32";
+  else
+    return "MINGW64";
+#else
+  return "CYGWIN";
+#endif
+}
+
 /* uname: POSIX 4.4.1.1 */
 
 /* New entrypoint for applications since API 335 */
@@ -36,7 +54,9 @@ uname_x (struct utsname *name)
 
       memset (name, 0, sizeof (*name));
       /* sysname */
-      __small_sprintf (name->sysname, "CYGWIN_%s-%u",
+      const char* sysname = get_sysname();
+      __small_sprintf (name->sysname, "%s_%s-%u",
+		       sysname,
 		       wincap.osname (), wincap.build_number ());
       /* nodename */
       memset (buf, 0, sizeof buf);
@@ -88,7 +108,7 @@ uname_x (struct utsname *name)
 /* Old entrypoint for applications up to API 334 */
 struct old_utsname
 {
-  char sysname[20];
+  char sysname[21];
   char nodename[20];
   char release[20];
   char version[20];
@@ -102,7 +122,8 @@ uname (struct utsname *in_name)
   __try
     {
       memset (name, 0, sizeof (*name));
-      __small_sprintf (name->sysname, "CYGWIN_%s", wincap.osname ());
+      const char* sysname = get_sysname();
+      __small_sprintf (name->sysname, "%s_%s", sysname, wincap.osname ());
 
       /* Computer name */
       cygwin_gethostname (name->nodename, sizeof (name->nodename) - 1);
diff --git a/winsup/cygwin/winver.rc b/winsup/cygwin/winver.rc
index 980d51204c..58878d41bd 100644
--- a/winsup/cygwin/winver.rc
+++ b/winsup/cygwin/winver.rc
@@ -35,7 +35,7 @@ BEGIN
       VALUE "InternalName", CYGWIN_DLL_NAME
       VALUE "LegalCopyright", "Copyright \251 Cygwin Authors 1996-" STRINGIFY(CYGWIN_BUILD_YEAR)
       VALUE "OriginalFilename", CYGWIN_DLL_NAME
-      VALUE "ProductName", "Cygwin"
+      VALUE "ProductName", "MSYS2"
       VALUE "ProductVersion", STRINGIFY(CYGWIN_VERSION)
       VALUE "APIVersion", CYGWIN_API_VERSION
       VALUE "SharedMemoryVersion", STRINGIFY(CYGWIN_VERSION_SHARED_DATA)
diff --git a/winsup/doc/Makefile.am b/winsup/doc/Makefile.am
index 650e0c9247..55e9b95e78 100644
--- a/winsup/doc/Makefile.am
+++ b/winsup/doc/Makefile.am
@@ -10,9 +10,7 @@ man1_MANS =
 man3_MANS =
 man5_MANS =
 
-doc_DATA = \
-	cygwin-ug-net/cygwin-ug-net.pdf \
-	cygwin-api/cygwin-api.pdf
+doc_DATA =
 
 htmldir = $(datarootdir)/doc
 
@@ -35,8 +33,7 @@ all-local: Makefile.dep \
 	cygwin-ug-net/cygwin-ug-net.html \
 	faq/faq.html faq/faq.body \
 	cygwin-ug-net/cygwin-ug-net-nochunks.html.gz \
-	api2man.stamp intro2man.stamp utils2man.stamp \
-	cygwin-api.info cygwin-ug-net.info
+	api2man.stamp intro2man.stamp utils2man.stamp
 
 clean-local:
 	rm -f Makefile.dep
@@ -76,7 +73,7 @@ install-etc:
 	@$(MKDIR_P) $(DESTDIR)$(sysconfdir)/preremove
 	$(INSTALL_SCRIPT) $(srcdir)/etc.preremove.cygwin-doc.sh $(DESTDIR)$(sysconfdir)/preremove/cygwin-doc.sh
 
-install-data-hook: install-extra-man install-html-local install-info-local install-etc
+install-data-hook: install-extra-man install-html-local install-etc
 
 uninstall-extra-man:
 	for i in *.1 ; do \
diff --git a/winsup/doc/cygwinenv.xml b/winsup/doc/cygwinenv.xml
index 5e17404a71..3051416bdd 100644
--- a/winsup/doc/cygwinenv.xml
+++ b/winsup/doc/cygwinenv.xml
@@ -73,7 +73,7 @@ time and when handles are inherited.  Defaults to set.</para>
 <listitem>
 <para><envar>(no)wincmdln</envar> - if set, the windows complete command
 line (truncated to ~32K) will be passed on any processes that it creates
-in addition to the normal UNIX argv list.  Defaults to not set.</para>
+in addition to the normal UNIX argv list.  Defaults to set.</para>
 </listitem>
 
 <listitem>
diff --git a/winsup/testsuite/config/default.exp b/winsup/testsuite/config/default.exp
index 7ef16ee6a9..fd592c3adf 100644
--- a/winsup/testsuite/config/default.exp
+++ b/winsup/testsuite/config/default.exp
@@ -1,11 +1,11 @@
 proc winsup_version {} {
     global env
     global runtime_root
-    clone_output "\n[exec grep -a ^%%% $runtime_root/cygwin0.dll]\n"
-    if { [info exists env(CYGWIN)] } {
-        clone_output "CYGWIN=$env(CYGWIN)\n"
+    clone_output "\n[exec grep -a ^%%% $runtime_root/msys0.dll]\n"
+    if { [info exists env(MSYS)] } {
+        clone_output "MSYS=$env(MSYS)\n"
     } else {
-        clone_output "CYGWIN=\n"
+        clone_output "MSYS=\n"
     }
 }
 
diff --git a/winsup/testsuite/cygrun.c b/winsup/testsuite/cygrun.c
index 65d859d598..616b0439f7 100644
--- a/winsup/testsuite/cygrun.c
+++ b/winsup/testsuite/cygrun.c
@@ -32,8 +32,8 @@ main (int argc, char **argv)
   if (argc >= 3)
     SetEnvironmentVariable ("TDIRECTORY", argv[2]);
 
-  SetEnvironmentVariable ("CYGWIN_TESTING", "1");
-  if ((p = getenv ("CYGWIN")) == NULL || (strstr (p, "ntsec") == NULL))
+  SetEnvironmentVariable ("MSYS_TESTING", "1");
+  if ((p = getenv ("MSYS")) == NULL || (strstr (p, "ntsec") == NULL))
     {
       char buf[4096];
       if (!p)
@@ -47,7 +47,7 @@ main (int argc, char **argv)
 	  strcat (buf, " ");
 	}
       strcat(buf, "ntsec");
-      SetEnvironmentVariable ("CYGWIN", buf);
+      SetEnvironmentVariable ("MSYS", buf);
     }
 
   memset (&sa, 0, sizeof (sa));
diff --git a/winsup/testsuite/winsup.api/cygload.cc b/winsup/testsuite/winsup.api/cygload.cc
index f5ca8db9a1..510a627c52 100644
--- a/winsup/testsuite/winsup.api/cygload.cc
+++ b/winsup/testsuite/winsup.api/cygload.cc
@@ -25,7 +25,7 @@
 		     save for errors.
      -testinterrupts Pauses the program for 30 seconds so you can demonstrate
 		     that it handles ^C properly.
-     -cygwin         Name of DLL to load.  Defaults to "cygwin1.dll". */
+     -cygwin         Name of DLL to load.  Defaults to "msys-2.0.dll". */
 
 #include "cygload.h"
 #include <iostream>
@@ -152,15 +152,15 @@ cygwin::connector::connector (const char *dll)
   if ((_library = LoadLibrary (dll)) == NULL)
     throw windows_error ("LoadLibrary", dll);
 
-  *out << "Initializing cygwin..." << endl;
+  *out << "Initializing msys..." << endl;
 
-  // This calls dcrt0.cc:cygwin_dll_init(), which calls dll_crt0_1(),
+  // This calls dcrt0.cc:msys_dll_init(), which calls dll_crt0_1(),
   // which will, among other things:
   // * spawn the cygwin signal handling thread from sigproc_init()
   // * initialize the thread-local storage for this thread and overwrite
   //   the first 4K of the stack
   void (*cyginit) ();
-  get_symbol ("cygwin_dll_init", cyginit);
+  get_symbol ("msys_dll_init", cyginit);
   (*cyginit) ();
 
   *out << "Loading symbols..." << endl;
@@ -224,7 +224,7 @@ cygwin::connector::~connector ()
 
     // This should call init.cc:dll_entry() with DLL_PROCESS_DETACH.
     if (!FreeLibrary (_library))
-      throw windows_error ("FreeLibrary", "cygwin1.dll");
+      throw windows_error ("FreeLibrary", "msys-2.0.dll");
   }
   catch (std::exception &x)
   {
@@ -490,7 +490,7 @@ main (int argc, char *argv[])
 
   std::ostringstream output;
   bool verbose = false, testinterrupts = false;
-  const char *dll = "cygwin1.dll";
+  const char *dll = "msys-2.0.dll";
 
   out = &output;
 
diff --git a/winsup/testsuite/winsup.api/cygload.exp b/winsup/testsuite/winsup.api/cygload.exp
index 8ba8249bbc..500683e4ce 100644
--- a/winsup/testsuite/winsup.api/cygload.exp
+++ b/winsup/testsuite/winsup.api/cygload.exp
@@ -32,7 +32,7 @@ if { $rv != {0 {}} } {
         set redirect_output /dev/null
     }
     set windows_runtime_root [exec cygpath -m $runtime_root]
-    ws_spawn "./mingw-cygload.exe -cygwin $windows_runtime_root/cygwin0.dll > $redirect_output"
+    ws_spawn "./mingw-cygload.exe -cygwin $windows_runtime_root/msys0.dll > $redirect_output"
     if { $rv != {0 {}} } {
         verbose -log "cygload: $rv"
         fail "cygload (execute)"
diff --git a/winsup/testsuite/winsup.api/cygload.h b/winsup/testsuite/winsup.api/cygload.h
index 8007fd5932..ab4003bd56 100644
--- a/winsup/testsuite/winsup.api/cygload.h
+++ b/winsup/testsuite/winsup.api/cygload.h
@@ -76,7 +76,7 @@ namespace cygwin
   // spawns a thread to let you receive signals from cygwin.
   class connector {
   public:
-    connector (const char *dll = "cygwin1.dll");
+    connector (const char *dll = "msys-2.0.dll");
     ~connector ();
 
     // A wrapper around GetProcAddress() for fetching symbols from the
diff --git a/winsup/testsuite/winsup.api/winsup.exp b/winsup/testsuite/winsup.api/winsup.exp
index 584aa57554..bc05713bd0 100644
--- a/winsup/testsuite/winsup.api/winsup.exp
+++ b/winsup/testsuite/winsup.api/winsup.exp
@@ -61,7 +61,7 @@ foreach src [lsort [glob -nocomplain $srcdir/$subdir/*.c $srcdir/$subdir/*/*.{cc
     if [ file exists "$srcdir/$subdir/$basename.exp" ] then {
 	source "$srcdir/$subdir/$basename.exp"
     } else {
-	ws_spawn "$CC -nodefaultlibs -mwin32 $CFLAGS $src $add_includes $add_libs $runtime_root/binmode.o -lgcc $runtime_root/libcygwin0.a -lkernel32 -luser32 -o $base.exe"
+	ws_spawn "$CC -nodefaultlibs -mwin32 $CFLAGS $src $add_includes $add_libs $runtime_root/binmode.o -lgcc $runtime_root/libmsys0.a -lkernel32 -luser32 -o $base.exe"
 	if { $rv } {
 	    fail "$testcase (compile)"
 	} else {
diff --git a/winsup/utils/Makefile.am b/winsup/utils/Makefile.am
index fa6499dfee..f10335eef5 100644
--- a/winsup/utils/Makefile.am
+++ b/winsup/utils/Makefile.am
@@ -88,6 +88,10 @@ profiler_CXXFLAGS = -I$(srcdir) -idirafter ${top_srcdir}/cygwin/local_includes -
 profiler_LDADD = $(LDADD) -lntdll
 cygps_LDADD = $(LDADD) -lpsapi -lntdll
 
+if HAVE_LIBSFRAME
+dumper_LDADD += -lsframe
+endif
+
 if CROSS_BOOTSTRAP
 SUBDIRS = mingw
 endif
diff --git a/winsup/utils/kill.cc b/winsup/utils/kill.cc
index fc984c0b47..05ecd13ac8 100644
--- a/winsup/utils/kill.cc
+++ b/winsup/utils/kill.cc
@@ -17,6 +17,7 @@ details. */
 #include <cygwin/version.h>
 #include <getopt.h>
 #include <limits.h>
+#include <cygwin/exit_process.h>
 
 static char *prog_name;
 
@@ -188,10 +189,20 @@ forcekill (pid_t pid, DWORD winpid, int sig, int wait)
       return;
     }
   if (!wait || WaitForSingleObject (h, 200) != WAIT_OBJECT_0)
-    if (sig && !TerminateProcess (h, sig << 8)
-	&& WaitForSingleObject (h, 200) != WAIT_OBJECT_0)
-      fprintf (stderr, "%s: couldn't kill pid %u, %u\n",
-	       prog_name, (unsigned int) dwpid, (unsigned int) GetLastError ());
+    {
+      HANDLE cur = GetCurrentProcess (), h2;
+      /* duplicate handle with access rights required for exit_process_tree() */
+      if (DuplicateHandle (cur, h, cur, &h2, PROCESS_CREATE_THREAD |
+			      PROCESS_QUERY_INFORMATION |
+			      PROCESS_VM_OPERATION |
+			      PROCESS_VM_WRITE | PROCESS_VM_READ |
+			      PROCESS_TERMINATE, FALSE, 0))
+      {
+        CloseHandle(h);
+        h = h2;
+      }
+      exit_process_tree (h, 128 + sig);
+    }
   CloseHandle (h);
 }
 
diff --git a/winsup/utils/ldd.cc b/winsup/utils/ldd.cc
index 0d073c2989..a31c4c6e44 100644
--- a/winsup/utils/ldd.cc
+++ b/winsup/utils/ldd.cc
@@ -249,7 +249,7 @@ tocyg (wchar_t *win_fn)
   return fn;
 }
 
-#define CYGWIN_DLL_LEN (wcslen (L"\\cygwin1.dll"))
+#define CYGWIN_DLL_LEN (wcslen (L"\\msys-2.0.dll"))
 static int
 print_dlls (dlls *dll, const wchar_t *dllfn, const wchar_t *process_fn)
 {
diff --git a/winsup/utils/loadlib.h b/winsup/utils/loadlib.h
index c83b76478f..42ffbfdc03 100644
--- a/winsup/utils/loadlib.h
+++ b/winsup/utils/loadlib.h
@@ -13,7 +13,7 @@
 #include <wchar.h>
 
 /* Load all system libs from the windows system directory by prepending the
-   full path.  This doesn't work for loadling cygwin1.dll.  For this case,
+   full path.  This doesn't work for loadling msys-2.0.dll.  For this case,
    instead of prepending the path, make sure that the CWD is removed from
    the DLL search path, if possible (XP SP1++, Vista++). */
 static HMODULE _load_sys_library (const wchar_t *dll) __attribute__ ((used));
@@ -45,8 +45,8 @@ _load_sys_library (const wchar_t *dll)
       	set_dll_directory (L"");
     }
 
-  if (wcscmp (dll, L"cygwin1.dll") == 0)
-    return LoadLibraryExW (L"cygwin1.dll", NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+  if (wcscmp (dll, L"msys-2.0.dll") == 0)
+    return LoadLibraryExW (L"msys-2.0.dll", NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
 
   wcscpy (dllpath, sysdir);
   wcscpy (dllpath + sysdir_len, dll);
diff --git a/winsup/utils/mingw/Makefile.am b/winsup/utils/mingw/Makefile.am
index c26eef80f8..d66c226e3a 100644
--- a/winsup/utils/mingw/Makefile.am
+++ b/winsup/utils/mingw/Makefile.am
@@ -26,6 +26,21 @@ bin_PROGRAMS = \
 	ldh \
 	strace
 
+libexec_PROGRAMS = getprocaddr32 getprocaddr64
+
+# Must *not* use -O2 here, as it screws up the stack backtrace
+getprocaddr32.o: %32.o: %.c
+	$(MINGW32_CC) -c -o $@ $<
+
+getprocaddr32.exe: %.exe: %.o
+	$(MINGW32_CC) -o $@ $^ -static -ldbghelp
+
+getprocaddr64.o: %64.o: %.c
+	$(MINGW64_CC) -c -o $@ $<
+
+getprocaddr64.exe: %.exe: %.o
+	$(MINGW64_CC) -o $@ $^ -static -ldbghelp
+
 cygcheck_SOURCES = \
 	bloda.cc \
 	cygcheck.cc \
diff --git a/winsup/utils/mingw/cygcheck.cc b/winsup/utils/mingw/cygcheck.cc
index 69f75927fc..aa87d53739 100644
--- a/winsup/utils/mingw/cygcheck.cc
+++ b/winsup/utils/mingw/cygcheck.cc
@@ -66,8 +66,7 @@ static const char *known_env_vars[] = {
   "c_include_path",
   "compiler_path",
   "cxx_include_path",
-  "cygwin",
-  "cygwin32",
+  "msys",
   "dejagnu",
   "expect",
   "gcc_default_options",
@@ -517,12 +516,12 @@ struct ImpDirectory
 
 static bool track_down (const char *file, const char *suffix, int lvl);
 
-#define CYGPREFIX (sizeof ("%%% Cygwin ") - 1)
+#define CYGPREFIX (sizeof ("%%% Msys ") - 1)
 static void
 cygwin_info (HANDLE h)
 {
   char *buf, *bufend, *buf_start = NULL;
-  const char *hello = "    Cygwin DLL version info:\n";
+  const char *hello = "    Msys DLL version info:\n";
   DWORD size = GetFileSize (h, NULL);
   DWORD n;
 
@@ -549,7 +548,7 @@ cygwin_info (HANDLE h)
   while (buf < bufend)
     if ((buf = (char *) memchr (buf, '%', bufend - buf)) == NULL)
       break;
-    else if (strncmp ("%%% Cygwin ", buf, CYGPREFIX) != 0)
+    else if (strncmp ("%%% Msys ", buf, CYGPREFIX) != 0)
       buf++;
     else
       {
@@ -743,7 +742,7 @@ dll_info (const char *path, HANDLE fh, int lvl, int recurse)
 	    }
 	}
     }
-  if (strstr (path, "\\cygwin1.dll"))
+  if (strstr (path, "\\msys-2.0.dll"))
     cygwin_info (fh);
 }
 
@@ -990,7 +989,7 @@ scan_registry (RegInfo * prev, HKEY hKey, char *name, int cygwin, bool wow64)
 
   char *cp;
   for (cp = name; *cp; cp++)
-    if (strncasecmp (cp, "Cygwin", 6) == 0)
+    if (strncasecmp (cp, "Msys", 4) == 0)
       cygwin = 1;
 
   DWORD num_subkeys, max_subkey_len, num_values;
@@ -1254,7 +1253,7 @@ dump_sysinfo_services ()
 
   /* inform the user if nothing found */
   if (no_services)
-    puts ("No Cygwin services found.\n");
+    puts ("No Msys services found.\n");
 }
 
 enum handle_reg_t
@@ -1269,10 +1268,10 @@ handle_reg_installation (handle_reg_t what)
   HKEY key;
 
   if (what == PRINT_KEY)
-    printf ("Cygwin installations found in the registry:\n");
+    printf ("Msys installations found in the registry:\n");
   for (int i = 0; i < 2; ++i)
     if (RegOpenKeyEx (i ? HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE,
-		      "SOFTWARE\\Cygwin\\Installations", 0,
+		      "SOFTWARE\\Msys\\Installations", 0,
 		      what == DELETE_KEY ? KEY_READ | KEY_WRITE : KEY_READ,
 		      &key)
 	== ERROR_SUCCESS)
@@ -1294,7 +1293,7 @@ handle_reg_installation (handle_reg_t what)
 	      if (what == PRINT_KEY)
 		printf ("  %s Key: %s Path: %s", i ? "User:  " : "System:",
 			name, path);
-	      strcat (path, "\\bin\\cygwin1.dll");
+	      strcat (path, "\\bin\\msys-2.0.dll");
 	      if (what == PRINT_KEY)
 		printf ("%s\n", access (path, F_OK) ? " (ORPHANED)" : "");
 	      else if (access (path, F_OK))
@@ -1368,7 +1367,7 @@ dump_sysinfo ()
       _wputenv (comspec);
     }
 
-  printf ("\nCygwin Configuration Diagnostics\n");
+  printf ("\nMsys Configuration Diagnostics\n");
   time (&now);
   printf ("Current System Time: %s\n", ctime (&now));
 
@@ -1638,7 +1637,7 @@ dump_sysinfo ()
 
 
   if (givehelp)
-    printf ("Here's some environment variables that may affect cygwin:\n");
+    printf ("Here's some environment variables that may affect msys:\n");
   for (i = 0; environ[i]; i++)
     {
       char *eq = strchr (environ[i], '=');
@@ -1688,7 +1687,7 @@ dump_sysinfo ()
   if (registry)
     {
       if (givehelp)
-	printf ("Scanning registry for keys with 'Cygwin' in them...\n");
+	printf ("Scanning registry for keys with 'Msys' in them...\n");
       scan_registry (0, HKEY_CURRENT_USER,
 		     (char *) "HKEY_CURRENT_USER", 0, false);
       scan_registry (0, HKEY_LOCAL_MACHINE,
@@ -1866,7 +1865,7 @@ dump_sysinfo ()
   printf ("\n");
 
   if (givehelp)
-    printf ("Looking for various Cygwin DLLs...  (-v gives version info)\n");
+    printf ("Looking for various Msys DLLs...  (-v gives version info)\n");
   int cygwin_dll_count = 0;
   char cygdll_path[32768];
   for (pathlike *pth = paths; pth->dir; pth++)
@@ -1883,10 +1882,10 @@ dump_sysinfo ()
 	  wcstombs (f, ffinfo.cFileName, sizeof f);
 	  if (strcasecmp (f + strlen (f) - 4, ".dll") == 0)
 	    {
-	      if (strncasecmp (f, "cyg", 3) == 0)
+	      if (strncasecmp (f, "msys-", 5) == 0)
 		{
 		  sprintf (tmp, "%s%s", pth->dir, f);
-		  if (strcasecmp (f, "cygwin1.dll") == 0)
+		  if (strcasecmp (f, "msys-2.0.dll") == 0)
 		    {
 		      if (!cygwin_dll_count)
 			strcpy (cygdll_path, pth->dir);
@@ -1910,9 +1909,9 @@ dump_sysinfo ()
       FindClose (ff);
     }
   if (cygwin_dll_count > 1)
-    puts ("Warning: There are multiple cygwin1.dlls on your path");
+    puts ("Warning: There are multiple msys-2.0.dlls on your path");
   if (!cygwin_dll_count)
-    puts ("Warning: cygwin1.dll not found on your path");
+    puts ("Warning: msys-2.0.dll not found on your path");
 
   dump_dodgy_apps (verbose);
 
@@ -2159,8 +2158,8 @@ static char opts[] = "cdsrvkflphV";
 static void
 print_version ()
 {
-  printf ("cygcheck (cygwin) %d.%d.%d\n"
-	  "System Checker for Cygwin\n"
+  printf ("cygcheck (msys) %d.%d.%d\n"
+	  "System Checker for Msys\n"
 	  "Copyright (C) 1998 - %s Cygwin Authors\n"
 	  "This is free software; see the source for copying conditions.  "
 	  "There is NO\n"
@@ -2192,7 +2191,7 @@ load_cygwin (int& argc, char **&argv)
 {
   HMODULE h;
 
-  if (!(h = LoadLibrary ("cygwin1.dll")))
+  if (!(h = LoadLibrary ("msys-2.0.dll")))
     return;
   GetModuleFileNameW (h, cygwin_dll_path, 32768);
   if ((cygwin_internal = (uintptr_t (*) (int, ...))
diff --git a/winsup/utils/mingw/getprocaddr.c b/winsup/utils/mingw/getprocaddr.c
new file mode 100644
index 0000000000..25814c7bdd
--- /dev/null
+++ b/winsup/utils/mingw/getprocaddr.c
@@ -0,0 +1,310 @@
+/* getprocaddr.c
+
+This program is a helper for getting the pointers for the
+functions in kernel32 module, and optionally injects a remote
+thread that runs those functions given a pid and exit code.
+
+We use dbghelp.dll to get the pointer to kernel32!CtrlRoutine
+because it isn't exported. For that, we try to generate console
+event (Ctrl+Break) ourselves, to find the pointer, and it is
+printed if asked to, or a remote thread is injected to run the
+given function.
+
+This software is a copyrighted work licensed under the terms of the
+Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+details. */
+
+#include <stdio.h>
+#include <windows.h>
+
+/* Include dbghelp.h after windows.h */
+#include <dbghelp.h>
+
+static DWORD pid;
+static uintptr_t exit_code;
+static HANDLE CtrlEvent;
+
+static int
+inject_remote_thread_into_process (HANDLE process,
+                                   LPTHREAD_START_ROUTINE address,
+                                   uintptr_t exit_code,
+                                   DWORD *thread_return)
+{
+  int res = -1;
+
+  if (!address)
+    return res;
+  DWORD thread_id;
+  HANDLE thread = CreateRemoteThread (process, NULL, 1024 * 1024, address,
+                                      (PVOID)exit_code, 0, &thread_id);
+  if (thread)
+    {
+      /*
+       * Wait up to 10 seconds (arbitrary constant) for the thread to finish;
+       * Maybe we should wait forever? I have seen Cmd does so, but well...
+       */
+      if (WaitForSingleObject (thread, 10000) == WAIT_OBJECT_0)
+        res = 0;
+      /*
+      According to the docs at MSDN for GetExitCodeThread, it will
+      get the return value from the function, here CtrlRoutine. So, this
+      checks if the Ctrl Event is handled correctly by the process.
+
+      By some testing I could see CtrlRoutine returns 0 in case where
+      CtrlEvent set by SetConsoleCtrlHandler is handled correctly, in all
+      other cases it returns something non-zero(not sure what it that).
+      */
+      if (thread_return != NULL)
+        GetExitCodeThread (thread, thread_return);
+
+      CloseHandle (thread);
+    }
+
+  return res;
+}
+
+/* Here, we send a CtrlEvent to the current process for the
+ * sole purpose of capturing the address of the CtrlRoutine
+ * function, by looking the stack trace.
+ *
+ * This hack is needed because we cannot use GetProcAddress()
+ * as we do for ExitProcess(), because CtrlRoutine is not
+ * exported (although the .pdb files ensure that we can see
+ * it in a debugger).
+ */
+static WINAPI BOOL
+ctrl_handler (DWORD ctrl_type)
+{
+  unsigned short count;
+  void *address;
+  HANDLE process;
+  PSYMBOL_INFOW info;
+  DWORD64 displacement;
+  DWORD thread_return = 0;
+
+  count = CaptureStackBackTrace (1l /* skip this function */,
+                                 1l /* return only one trace item */, &address,
+                                 NULL);
+  if (count != 1)
+    {
+      fprintf (stderr, "Could not capture backtrace\n");
+      return FALSE;
+    }
+
+  process = GetCurrentProcess ();
+  if (!SymInitialize (process, NULL, TRUE))
+    {
+      fprintf (stderr, "Could not initialize symbols\n");
+      return FALSE;
+    }
+
+  info = (PSYMBOL_INFOW)malloc (sizeof (*info)
+                                + MAX_SYM_NAME * sizeof (wchar_t));
+  if (!info)
+    {
+      fprintf (stderr, "Could not allocate symbol info structure\n");
+      return FALSE;
+    }
+  info->SizeOfStruct = sizeof (*info);
+  info->MaxNameLen = MAX_SYM_NAME;
+
+  if (!SymFromAddrW (process, (DWORD64) (intptr_t)address, &displacement,
+                     info))
+    {
+      fprintf (stderr, "Could not get symbol info\n");
+      SymCleanup (process);
+      return FALSE;
+    }
+
+  if (pid == 0)
+    {
+      printf ("%p\n", (void *)(intptr_t)info->Address);
+    }
+  else
+    {
+      LPTHREAD_START_ROUTINE address =
+        (LPTHREAD_START_ROUTINE) (intptr_t)info->Address;
+      HANDLE h = OpenProcess (PROCESS_CREATE_THREAD |
+                              PROCESS_QUERY_INFORMATION |
+                              PROCESS_VM_OPERATION |
+                              PROCESS_VM_WRITE |
+                              PROCESS_VM_READ, FALSE, pid);
+      if (h == NULL)
+        {
+          fprintf (stderr, "OpenProcess failed: %ld\n", GetLastError ());
+          return 1;
+        }
+      /* Inject the remote thread only when asked to */
+      if (inject_remote_thread_into_process (h, address, exit_code,
+                                             &thread_return) < 0)
+        {
+          fprintf (stderr,
+                   "Error while injecting remote thread for pid(%lu)\n", pid);
+          exit (1); /*We should exit immediately or else there will a 10s hang
+                       waiting for the event to happen.*/
+        }
+      if (thread_return)
+        fprintf (stderr,
+                 "Injected remote thread for pid(%lu) returned %lu\n", pid,
+                 thread_return);
+    }
+  SymCleanup (process);
+  if (!SetEvent (CtrlEvent))
+    {
+      fprintf (stderr, "SetEvent failed (%ld)\n", GetLastError ());
+      return 1;
+    }
+  exit (thread_return != 0);
+}
+
+/* The easy route for finding the address of CtrlRoutine
+ * would be use GetProcAddress() but this isn't viable
+ * here because that symbol isn't exported.
+ */
+static int
+find_ctrl_routine_the_hard_way ()
+{
+  /*
+   * Avoid terminating all processes attached to the current console;
+   * This would happen if we used the same console as the caller, though,
+   * because we are sending a CtrlEvent on purpose (which _is_ sent to
+   * all processes connected to the same console, and the other processes
+   * are most likely unprepared for that CTRL_BREAK_EVENT and would be
+   * terminated as a consequence, _including the caller_).
+   *
+   * In case we get only one result from GetConsoleProcessList(), we don't
+   * need to create and allocate a new console, and it could avoid a console
+   * window popping up.
+   */
+  DWORD proc_lists;
+  if (GetConsoleProcessList (&proc_lists, 5) > 1)
+    {
+      if (!FreeConsole () && GetLastError () != ERROR_INVALID_PARAMETER)
+        {
+          fprintf (stderr, "Could not detach from current Console: %ld\n",
+                   GetLastError ());
+          return 1;
+        }
+      if (!AllocConsole ())
+        {
+          fprintf (stderr, "Could not allocate a new Console\n");
+          return 1;
+        }
+    }
+
+  CtrlEvent = CreateEvent (NULL,  // default security attributes
+                           TRUE,  // manual-reset event
+                           FALSE, // initial state is nonsignaled
+                           NULL   // object name
+  );
+
+  if (CtrlEvent == NULL)
+    {
+      fprintf (stderr, "CreateEvent failed (%ld)\n", GetLastError ());
+      return 1;
+    }
+
+
+  if (!SetConsoleCtrlHandler (ctrl_handler, TRUE))
+    {
+      fprintf (stderr, "Could not register Ctrl handler\n");
+      return 1;
+    }
+
+  if (!GenerateConsoleCtrlEvent (CTRL_BREAK_EVENT, 0))
+    {
+      fprintf (stderr, "Could not simulate Ctrl+Break\n");
+      return 1;
+    }
+
+  if (WaitForSingleObject (CtrlEvent, 10000 /* 10 seconds*/) != WAIT_OBJECT_0)
+    {
+      fprintf (stderr, "WaitForSingleObject failed (%ld)\n", GetLastError ());
+      return 1;
+    }
+  return 0;
+}
+
+static void *
+get_proc_addr (const char * module_name, const char * function_name)
+{
+      HMODULE module = GetModuleHandle (module_name);
+      if (!module)
+        return NULL;
+      return (void *)GetProcAddress (module, function_name);
+}
+
+int
+main (int argc, char **argv)
+{
+  char *end;
+  void *address;
+  BOOL is_ctrl_routine;
+  DWORD thread_return = 0;
+
+  if (argc == 4)
+    {
+      exit_code = atoi (argv[2]);
+      pid = strtoul (argv[3], NULL, 0);
+    }
+  else if (argc == 2)
+    {
+      pid = 0;
+    }
+  else
+    {
+      fprintf (stderr, "Need a function name, exit code and pid\n"
+               "Or needs a function name.\n");
+      return 1;
+    }
+
+  is_ctrl_routine = strcmp (argv[1], "CtrlRoutine") == 0;
+  address = get_proc_addr ("kernel32", argv[1]);
+  if (is_ctrl_routine && !address)
+    {
+      /* CtrlRoutine is undocumented, and has been seen in both
+       * kernel32 and kernelbase
+       */
+      address = get_proc_addr ("kernelbase", argv[1]);
+      if (!address)
+        return find_ctrl_routine_the_hard_way ();
+    }
+
+  if (!address)
+    {
+      fprintf (stderr, "Could not get proc address\n");
+      return 1;
+    }
+
+  if (pid == 0)
+    {
+      printf ("%p\n", address);
+      fflush (stdout);
+      return 0;
+    }
+  HANDLE h = OpenProcess (PROCESS_CREATE_THREAD |
+                          PROCESS_QUERY_INFORMATION | PROCESS_VM_OPERATION |
+                          PROCESS_VM_WRITE | PROCESS_VM_READ, FALSE, pid);
+  if (h == NULL)
+    {
+      fprintf (stderr, "OpenProcess failed: %ld\n", GetLastError ());
+      return 1;
+    }
+  /* Inject the remote thread */
+  if (inject_remote_thread_into_process (h, (LPTHREAD_START_ROUTINE)address,
+                                         exit_code, &thread_return) < 0)
+    {
+      fprintf (stderr, "Could not inject thread into process %lu\n", pid);
+      return 1;
+    }
+
+  if (is_ctrl_routine && thread_return)
+    {
+      fprintf (stderr,
+               "Injected remote thread for pid %lu returned %lu\n", pid,
+               thread_return);
+      return 1;
+    }
+
+  return 0;
+}
diff --git a/winsup/utils/mingw/strace.cc b/winsup/utils/mingw/strace.cc
index c220643b33..f6186beeb6 100644
--- a/winsup/utils/mingw/strace.cc
+++ b/winsup/utils/mingw/strace.cc
@@ -284,7 +284,7 @@ load_cygwin ()
   if (h)
     return 0;
 
-  if (!(h = LoadLibrary ("cygwin1.dll")))
+  if (!(h = LoadLibrary ("msys-2.0.dll")))
     {
       errno = ENOENT;
       return 0;
@@ -352,20 +352,40 @@ create_child (char **argv)
     flags |= CREATE_NEW_CONSOLE | CREATE_NEW_PROCESS_GROUP;
 
   make_command_line (one_line, argv);
+  if (!quiet)
+    printf ("create_child: %s\n", one_line.buf);
 
   SetConsoleCtrlHandler (NULL, 0);
-
-  const char *cygwin_env = getenv ("CYGWIN");
+/* Commit message for this code was:
+"* strace.cc (create_child): Set CYGWIN=noglob when starting new process so that
+
+  Cygwin will leave already-parsed the command line alonw."
+
+  I can see no reason for it and it badly breaks the ability to use
+  strace.exe to investigate calling a Cygwin program from a Windows
+  program, for example:
+  strace mingw32-make.exe
+  .. where mingw32-make.exe finds sh.exe and uses it as the shell.
+  The reason it badly breaks this use-case is because dcrt0.cc depends
+  on globbing to happen to parse commandlines from Windows programs;
+  irrespective of whether they contain any glob patterns or not.
+  
+  See quoted () comment:
+  "This must have been run from a Windows shell, so preserve
+     quotes for globify to play with later."
+
+  const char *cygwin_env = getenv ("MSYS");
   const char *space;
 
-  if (cygwin_env && strlen (cygwin_env) <= 256) /* sanity check */
+  if (cygwin_env && strlen (cygwin_env) <= 256) // sanity check
     space = " ";
   else
     space = cygwin_env = "";
-  char *newenv = (char *) malloc (sizeof ("CYGWIN=noglob")
+  char *newenv = (char *) malloc (sizeof ("MSYS=noglob")
 				  + strlen (space) + strlen (cygwin_env));
-  sprintf (newenv, "CYGWIN=noglob%s%s", space, cygwin_env);
+  sprintf (newenv, "MSYS=noglob%s%s", space, cygwin_env);
   _putenv (newenv);
+*/
   ret = CreateProcess (0, one_line.buf,	/* command line */
 		       NULL,	/* Security */
 		       NULL,	/* thread */
@@ -815,7 +835,7 @@ dotoggle (pid_t pid)
   child_pid = (DWORD) cygwin_internal (CW_CYGWIN_PID_TO_WINPID, pid);
   if (!child_pid)
     {
-      warn (0, "no such cygwin pid - %d", pid);
+      warn (0, "no such msys pid - %d", pid);
       child_pid = pid;
     }
   if (cygwin_internal (CW_STRACE_TOGGLE, child_pid))
diff --git a/winsup/utils/path.cc b/winsup/utils/path.cc
index fe55a646d9..323e4c784b 100644
--- a/winsup/utils/path.cc
+++ b/winsup/utils/path.cc
@@ -585,14 +585,14 @@ read_mounts ()
     }
   max_mount_entry = 0;
 
-  /* First fetch the cygwin1.dll path from the LoadLibrary call in load_cygwin.
-     This utilizes the DLL search order to find a matching cygwin1.dll and to
+  /* First fetch the msys-2.0.dll path from the LoadLibrary call in load_cygwin.
+     This utilizes the DLL search order to find a matching msys-2.0.dll and to
      compute the installation path from that DLL's path. */
   if (cygwin_dll_path[0])
     wcscpy (path, cygwin_dll_path);
-  /* If we can't load cygwin1.dll, check where cygcheck is living itself and
-     try to fetch installation path from here.  Does cygwin1.dll exist in the
-     same path?  This should only kick in if the cygwin1.dll in the same path
+  /* If we can't load msys-2.0.dll, check where cygcheck is living itself and
+     try to fetch installation path from here.  Does msys-2.0.dll exist in the
+     same path?  This should only kick in if the msys-2.0.dll in the same path
      has been made non-executable for the current user accidentally. */
   else if (!GetModuleFileNameW (NULL, path, 32768))
     return;
@@ -601,7 +601,7 @@ read_mounts ()
     {
       if (!cygwin_dll_path[0])
 	{
-	  wcscpy (path_end, L"\\cygwin1.dll");
+	  wcscpy (path_end, L"\\msys-2.0.dll");
 	  DWORD attr = GetFileAttributesW (path);
 	  if (attr == (DWORD) -1
 	      || (attr & (FILE_ATTRIBUTE_DIRECTORY
diff --git a/winsup/utils/ssp.c b/winsup/utils/ssp.c
index 96a90a1d98..95045e1e8b 100644
--- a/winsup/utils/ssp.c
+++ b/winsup/utils/ssp.c
@@ -710,15 +710,15 @@ usage (FILE * stream)
     "You must specify the range of memory addresses to keep track of\n"
     "manually, but it's not hard to figure out what to specify.  Use the\n"
     "\"objdump\" program to determine the bounds of the target's \".text\"\n"
-    "section.  Let's say we're profiling cygwin1.dll.  Make sure you've\n"
+    "section.  Let's say we're profiling msys-2.0.dll.  Make sure you've\n"
     "built it with debug symbols (else gprof won't run) and run objdump\n"
     "like this:\n"
     "\n"
-    "	objdump -h cygwin1.dll\n"
+    "	objdump -h msys-2.0.dll\n"
     "\n"
     "It will print a report like this:\n"
     "\n"
-    "cygwin1.dll:     file format pei-i386\n"
+    "msys-2.0.dll:     file format pei-i386\n"
     "\n"
     "Sections:\n"
     "Idx Name          Size      VMA       LMA       File off  Algn\n"
@@ -749,7 +749,7 @@ usage (FILE * stream)
     "\"gmon.out\".  You can turn this data file into a readable report with\n"
     "gprof:\n"
     "\n"
-    "	gprof -b cygwin1.dll\n"
+    "	gprof -b msys-2.0.dll\n"
     "\n"
     "The \"-b\" means 'skip the help pages'.  You can omit this until you're\n"
     "familiar with the report layout.  The gprof documentation explains\n"