Review fixups

Makefile

@@ -12,19 +12,23 @@ PREFIX?=c:/wasi-sdk
 # who knows what
 BASH?=bash -c
 
-ifneq (x$(MSYSTEM),x)
+ifeq (x$(MSYSTEM),x)
+$(error On Windows, this Makefile only works in MSYS2 environments such as git-bash.)
+endif
+
 # msys needs any /-prefixed arguments, or =/ containing, to turn into //
 # because it tries to path-expand the / into the msys root.  // escapes this.
-SLASHY_SLASH=/
-# assuming we're running under msys2 (git-bash), PATH needs /c/foo format directories
+ESCAPE_SLASH=/
+
+# assuming we're running under msys2 (git-bash), PATH needs /c/foo format directories (because
+# it itself is :-delimited)
 PATH_PREFIX=$(shell cygpath.exe -u $(PREFIX))
-endif
 
 endif
 
 PREFIX?=/opt/wasi-sdk
 PATH_PREFIX?=$(PREFIX)
-SLASHY_SLASH?=
+ESCAPE_SLASH?=
 BASH?=
 
 CLANG_VERSION=$(shell $(BASH) ./llvm_version.sh $(LLVM_PROJ_DIR))
@@ -131,7 +135,7 @@ build/libcxx.BUILT: build/llvm.BUILT build/compiler-rt.BUILT build/wasi-libc.BUI
 	cd build/libcxx && cmake -G Ninja $(LIBCXX_CMAKE_FLAGS) \
 	    -DCMAKE_C_FLAGS="$(DEBUG_PREFIX_MAP)" \
 	    -DCMAKE_CXX_FLAGS="$(DEBUG_PREFIX_MAP)" \
-	    -DLIBCXX_LIBDIR_SUFFIX=$(SLASHY_SLASH)/wasm32-wasi \
+	    -DLIBCXX_LIBDIR_SUFFIX=$(ESCAPE_SLASH)/wasm32-wasi \
 	    $(LLVM_PROJ_DIR)/libcxx
 	ninja $(NINJA_FLAGS) -v -C build/libcxx
 	# Do the install.
@@ -169,7 +173,7 @@ build/libcxxabi.BUILT: build/libcxx.BUILT build/llvm.BUILT
 	cd build/libcxxabi && cmake -G Ninja $(LIBCXXABI_CMAKE_FLAGS) \
 	    -DCMAKE_C_FLAGS="$(DEBUG_PREFIX_MAP)" \
 	    -DCMAKE_CXX_FLAGS="$(DEBUG_PREFIX_MAP)" \
-	    -DLIBCXXABI_LIBDIR_SUFFIX=$(SLASHY_SLASH)/wasm32-wasi \
+	    -DLIBCXXABI_LIBDIR_SUFFIX=$(ESCAPE_SLASH)/wasm32-wasi \
 	    $(LLVM_PROJ_DIR)/libcxxabi
 	ninja $(NINJA_FLAGS) -v -C build/libcxxabi
 	# Do the install.

tar_from_installation.sh

@@ -1,19 +1,22 @@
 #!/usr/bin/env bash
 set -ex
-OUTDIR=$PWD/dist
-VERSION=`./version.sh`
-INDIR=/opt/wasi-sdk
 
 if [ -n "$1" ]; then
     OUTDIR=$1
+else
+    OUTDIR=$PWD/dist
 fi
 
 if [ -n "$2" ]; then
     VERSION="$2"
+else
+    VERSION=`./version.sh`
 fi
 
 if [ -n "$3" ]; then
-    INDIR="$3"
+    INSTALL_DIR="$3"
+else
+    INSTALL_DIR=/opt/wasi-sdk
 fi
 
 PKGDIR=build/wasi-sdk-$VERSION
@@ -26,8 +29,13 @@ case "$(uname -s)" in
     *)          MACHINE="UNKNOWN"
 esac
 
+if [ ! -d $INSTALL_DIR ] ; then
+    echo "Directory $INSTALL_DIR doesn't exist.  Nothing to copy from."
+    exit 1
+fi
+
 rm -rf $PKGDIR
-cp -R $INDIR $PKGDIR
+cp -R $INSTALL_DIR $PKGDIR
 cd build
 tar czf $OUTDIR/wasi-sdk-$VERSION\-$MACHINE.tar.gz wasi-sdk-$VERSION