From a613d444f95bbb1b504de3e2a6ba569da6b98109 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Thu, 18 Nov 2021 13:32:08 +0100
Subject: [PATCH 1/5] bpo-45573: Move mandatory core modules to
 Modules/Setup.core

Signed-off-by: Christian Heimes <christian@python.org>
---
 Makefile.pre.in                               |  3 ++
 .../2021-11-18-13-31-02.bpo-45573.LCjGB8.rst  |  1 +
 Modules/Setup                                 | 27 +----------
 Modules/Setup.core                            | 34 ++++++++++++++
 configure                                     | 45 ++++++++++++++++++-
 configure.ac                                  | 27 ++++++++++-
 setup.py                                      | 14 +++---
 7 files changed, 117 insertions(+), 34 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
 create mode 100644 Modules/Setup.core

diff --git a/Makefile.pre.in b/Makefile.pre.in
index 2e42d53d5b9869..a3a79c887f00c1 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -910,10 +910,12 @@ Makefile Modules/config.c: Makefile.pre \
 				$(MAKESETUP) \
 				$(srcdir)/Modules/Setup \
 				Modules/Setup.local \
+				$(srcdir)/Modules/Setup.core \
 				Modules/Setup.stdlib
 	$(SHELL) $(MAKESETUP) -c $(srcdir)/Modules/config.c.in \
 				-s Modules \
 				Modules/Setup.local \
+				$(srcdir)/Modules/Setup.core \
 				$(srcdir)/Modules/Setup
 	@mv config.c Modules
 	@echo "The Makefile was updated, you may need to re-run make."
@@ -2167,6 +2169,7 @@ libainstall:	@DEF_MAKE_RULE@ python-config
 	$(INSTALL_DATA) $(srcdir)/Modules/config.c.in $(DESTDIR)$(LIBPL)/config.c.in
 	$(INSTALL_DATA) Makefile $(DESTDIR)$(LIBPL)/Makefile
 	$(INSTALL_DATA) $(srcdir)/Modules/Setup $(DESTDIR)$(LIBPL)/Setup
+	$(INSTALL_DATA) $(srcdir)/Modules/Setup.core $(DESTDIR)$(LIBPL)/Setup.core
 	$(INSTALL_DATA) Modules/Setup.stdlib $(DESTDIR)$(LIBPL)/Setup.stdlib
 	$(INSTALL_DATA) Modules/Setup.local $(DESTDIR)$(LIBPL)/Setup.local
 	$(INSTALL_DATA) Misc/python.pc $(DESTDIR)$(LIBPC)/python-$(VERSION).pc
diff --git a/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst b/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
new file mode 100644
index 00000000000000..fbb63026669cc7
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
@@ -0,0 +1 @@
+Mandatory core modules are now in ``Modules/Setup.core``
diff --git a/Modules/Setup b/Modules/Setup
index f8c90ea77721dd..54abb17a4fd711 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -111,31 +111,8 @@ PYTHONPATH=$(COREPYTHONPATH)
 
 
 # ---
-# Built-in modules required to get a functioning interpreter;
-# cannot be built as shared!
-
-_collections _collectionsmodule.c
-_abc _abc.c
-_codecs _codecsmodule.c
-_functools _functoolsmodule.c
-_io -I$(srcdir)/Modules/_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c
-_locale _localemodule.c
-_operator _operator.c
-_signal signalmodule.c
-_sre _sre.c
-_stat _stat.c
-_symtable symtablemodule.c
-_thread _threadmodule.c
-_tracemalloc _tracemalloc.c  # See bpo-35053 as to why this is built in.
-_weakref _weakref.c
-atexit atexitmodule.c
-errno errnomodule.c
-faulthandler faulthandler.c
-itertools itertoolsmodule.c
-posix posixmodule.c
-pwd pwdmodule.c
-time timemodule.c
-
+# Built-in modules required to get a functioning interpreter are listed in
+# Modules/Setup.core.
 
 # ---
 # The rest of the modules listed in this file are all commented out by
diff --git a/Modules/Setup.core b/Modules/Setup.core
new file mode 100644
index 00000000000000..d543f087b89fc2
--- /dev/null
+++ b/Modules/Setup.core
@@ -0,0 +1,34 @@
+# -*- makefile -*-
+
+# ---
+# Built-in modules required to get a functioning interpreter;
+# cannot be built as shared!
+
+# module C APIs are used in core
+atexit atexitmodule.c
+faulthandler faulthandler.c
+posix posixmodule.c
+_signal signalmodule.c
+_tracemalloc _tracemalloc.c
+
+# modules used by importlib, deepfreeze, freeze, runpy, and sysconfig
+_codecs _codecsmodule.c
+_collections _collectionsmodule.c
+errno errnomodule.c
+_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c
+itertools itertoolsmodule.c
+_sre _sre.c
+_thread _threadmodule.c
+time timemodule.c
+_weakref _weakref.c
+
+# commonly used core modules
+_abc _abc.c
+_functools _functoolsmodule.c
+_locale _localemodule.c
+_operator _operator.c
+_stat _stat.c
+_symtable symtablemodule.c
+
+# for systems without $HOME env, used by site._getuserbase()
+pwd pwdmodule.c
diff --git a/configure b/configure
index 657c71dca62bdd..f11e2926b8220a 100755
--- a/configure
+++ b/configure
@@ -19456,6 +19456,49 @@ MODULE_BLOCK=
 
 
 
+# This is what autoupdate's m4 run will expand.  It fires
+# the warning (with _au_warn_XXX), outputs it into the
+# updated configure.ac (with AC_DIAGNOSE), and then outputs
+# the replacement expansion.
+
+
+# This is an auxiliary macro that is also run when
+# autoupdate runs m4.  It simply calls m4_warning, but
+# we need a wrapper so that each warning is emitted only
+# once.  We break the quoting in m4_warning's argument in
+# order to expand this macro's arguments, not AU_DEFUN's.
+
+
+# Finally, this is the expansion that is picked up by
+# autoconf.  It tells the user to run autoupdate, and
+# then outputs the replacement expansion.  We do not care
+# about autoupdate's warning because that contains
+# information on what to do *after* running autoupdate.
+
+
+
+
+    as_fn_append MODULE_BLOCK "MODULE_IO_CFLAGS=-I\$(srcdir)/Modules/_io$as_nl"
+
+
+    as_fn_append MODULE_BLOCK "MODULE_IO_LDFLAGS=$TIMEMODULE_LIB$as_nl"
+
+
+
+
+
+
+    as_fn_append MODULE_BLOCK "MODULE_TIME_LDFLAGS=$TIMEMODULE_LIB$as_nl"
+
+
+
+
+
+    as_fn_append MODULE_BLOCK "MODULE__DATETIME_LDFLAGS=$TIMEMODULE_LIB$as_nl"
+
+
+
+
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for stdlib extension module ossaudiodev" >&5
 $as_echo_n "checking for stdlib extension module ossaudiodev... " >&6; }
       case $py_stdlib_not_available in #(
@@ -21068,7 +21111,7 @@ fi
 echo "creating Makefile" >&6
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local $srcdir/Modules/Setup
+			Modules/Setup.local $srcdir/Modules/Setup.core $srcdir/Modules/Setup
 mv config.c Modules
 
 if test -z "$PKG_CONFIG"; then
diff --git a/configure.ac b/configure.ac
index 4bac7ccf2484ea..94c7a886913b6f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6030,6 +6030,31 @@ AC_DEFUN([PY_STDLIB_MOD], [
   m4_popdef([modstate])dnl
 ])
 
+dnl Define simple, always enabled stdlib extension module
+dnl PY_STDLIB_MOD_SIMPLE([NAME], [CFLAGS], [LDFLAGS])
+dnl cflags and ldflags are optional
+AC_DEFUN([PY_STDLIB_MOD_SIMPLE], [
+  m4_pushdef([modcond], [MODULE_]m4_toupper([$1]))dnl
+  dnl _MODULE_BLOCK_ADD(modcond, [yes])
+  dnl AM_CONDITIONAL(modcond, [true])
+  m4_ifval([$2], [
+    _MODULE_BLOCK_ADD([MODULE_]m4_toupper([$1])[_CFLAGS], [$2])
+  ])
+  m4_ifval([$3], [
+    _MODULE_BLOCK_ADD([MODULE_]m4_toupper([$1])[_LDFLAGS], [$3])
+  ])
+  m4_popdef([modcond])dnl
+])
+dnl alias for static core modules (Modules/Setup.core)
+AU_ALIAS([PY_STDLIB_MOD_CORE], [PY_STDLIB_MOD_SIMPLE])
+
+dnl static modules in Modules/Setup.core
+PY_STDLIB_MOD_SIMPLE([io], [-I\$(srcdir)/Modules/_io], [$TIMEMODULE_LIB])
+
+dnl always enabled extension modules
+PY_STDLIB_MOD_SIMPLE([time], [], [$TIMEMODULE_LIB])
+PY_STDLIB_MOD_SIMPLE([_datetime], [], [$TIMEMODULE_LIB])
+
 dnl platform specific extensions
 PY_STDLIB_MOD([ossaudiodev],
   [], [test "$ac_cv_header_linux_soundcard_h" = yes -o "$ac_cv_header_sys_soundcard_h" = yes])
@@ -6062,7 +6087,7 @@ fi
 echo "creating Makefile" >&AS_MESSAGE_FD
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local $srcdir/Modules/Setup
+			Modules/Setup.local $srcdir/Modules/Setup.core $srcdir/Modules/Setup
 mv config.c Modules
 
 if test -z "$PKG_CONFIG"; then
diff --git a/setup.py b/setup.py
index 040f90af601cce..fb9fd2b498d55e 100644
--- a/setup.py
+++ b/setup.py
@@ -1006,9 +1006,9 @@ def detect_simple_extensions(self):
         if lib:
             time_libs.append(lib)
 
-        # time operations and variables
-        self.add(Extension('time', ['timemodule.c'],
-                           libraries=time_libs))
+        # time operations and variables, always built by Modules/Setup.core
+        # self.add(Extension('time', ['timemodule.c'],
+        #                    libraries=time_libs))
         # libm is needed by delta_new() that uses round() and by accum() that
         # uses modf().
         self.add(Extension('_datetime', ['_datetimemodule.c'],
@@ -1034,8 +1034,8 @@ def detect_simple_extensions(self):
         self.add(Extension('_opcode', ['_opcode.c']))
         # asyncio speedups
         self.add(Extension("_asyncio", ["_asynciomodule.c"]))
-        # _abc speedups
-        self.add(Extension("_abc", ["_abc.c"]))
+        # _abc speedups, always built by Modules/Setup.core
+        # self.add(Extension("_abc", ["_abc.c"]))
         # _queue module
         self.add(Extension("_queue", ["_queuemodule.c"]))
         # _statistics module
@@ -1054,8 +1054,8 @@ def detect_simple_extensions(self):
             libs = ['bsd']
         self.add(Extension('fcntl', ['fcntlmodule.c'],
                            libraries=libs))
-        # pwd(3)
-        self.add(Extension('pwd', ['pwdmodule.c']))
+        # pwd(3), always built by Modules/Setup.core
+        # self.add(Extension('pwd', ['pwdmodule.c']))
         # grp(3)
         if not VXWORKS:
             self.add(Extension('grp', ['grpmodule.c']))

From 8c29e5290f714ed6090792944fdd19a31df4bfd7 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Fri, 19 Nov 2021 09:49:48 +0100
Subject: [PATCH 2/5] Use Setup.bootstrap

---
 Makefile.pre.in                               |  6 +-
 .../2021-11-18-13-31-02.bpo-45573.LCjGB8.rst  |  3 +-
 Modules/{Setup.core => Setup.bootstrap}       |  0
 Modules/Setup.stdlib.in                       |  3 +
 configure                                     | 65 ++++++++++++-------
 configure.ac                                  | 15 ++---
 setup.py                                      | 13 ++--
 7 files changed, 61 insertions(+), 44 deletions(-)
 rename Modules/{Setup.core => Setup.bootstrap} (100%)

diff --git a/Makefile.pre.in b/Makefile.pre.in
index a3a79c887f00c1..312e52486f2960 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -910,12 +910,12 @@ Makefile Modules/config.c: Makefile.pre \
 				$(MAKESETUP) \
 				$(srcdir)/Modules/Setup \
 				Modules/Setup.local \
-				$(srcdir)/Modules/Setup.core \
+				$(srcdir)/Modules/Setup.bootstrap \
 				Modules/Setup.stdlib
 	$(SHELL) $(MAKESETUP) -c $(srcdir)/Modules/config.c.in \
 				-s Modules \
 				Modules/Setup.local \
-				$(srcdir)/Modules/Setup.core \
+				$(srcdir)/Modules/Setup.bootstrap \
 				$(srcdir)/Modules/Setup
 	@mv config.c Modules
 	@echo "The Makefile was updated, you may need to re-run make."
@@ -2169,7 +2169,7 @@ libainstall:	@DEF_MAKE_RULE@ python-config
 	$(INSTALL_DATA) $(srcdir)/Modules/config.c.in $(DESTDIR)$(LIBPL)/config.c.in
 	$(INSTALL_DATA) Makefile $(DESTDIR)$(LIBPL)/Makefile
 	$(INSTALL_DATA) $(srcdir)/Modules/Setup $(DESTDIR)$(LIBPL)/Setup
-	$(INSTALL_DATA) $(srcdir)/Modules/Setup.core $(DESTDIR)$(LIBPL)/Setup.core
+	$(INSTALL_DATA) $(srcdir)/Modules/Setup.bootstrap $(DESTDIR)$(LIBPL)/Setup.bootstrap
 	$(INSTALL_DATA) Modules/Setup.stdlib $(DESTDIR)$(LIBPL)/Setup.stdlib
 	$(INSTALL_DATA) Modules/Setup.local $(DESTDIR)$(LIBPL)/Setup.local
 	$(INSTALL_DATA) Misc/python.pc $(DESTDIR)$(LIBPC)/python-$(VERSION).pc
diff --git a/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst b/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
index fbb63026669cc7..5f388948fb50fd 100644
--- a/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
+++ b/Misc/NEWS.d/next/Build/2021-11-18-13-31-02.bpo-45573.LCjGB8.rst
@@ -1 +1,2 @@
-Mandatory core modules are now in ``Modules/Setup.core``
+Mandatory core modules, that are required to bootstrap Python, are now in
+``Modules/Setup.bootstrap``.
diff --git a/Modules/Setup.core b/Modules/Setup.bootstrap
similarity index 100%
rename from Modules/Setup.core
rename to Modules/Setup.bootstrap
diff --git a/Modules/Setup.stdlib.in b/Modules/Setup.stdlib.in
index 2e87b032e35e8e..3b0d3227bc5b04 100644
--- a/Modules/Setup.stdlib.in
+++ b/Modules/Setup.stdlib.in
@@ -29,6 +29,9 @@
 ############################################################################
 # Modules that should always be present (POSIX and Windows):
 
+# needs libm and on some platforms librt
+@MODULE__DATETIME_TRUE@_datetime _datetimemodule.c
+
 # _decimal uses libmpdec
 # either static libmpdec.a from Modules/_decimal/libmpdec or libmpdec.so
 # with ./configure --with-system-libmpdec
diff --git a/configure b/configure
index f11e2926b8220a..9d03d89a241ef4 100755
--- a/configure
+++ b/configure
@@ -634,6 +634,12 @@ MODULE_PYEXPAT_FALSE
 MODULE_PYEXPAT_TRUE
 MODULE_OSSAUDIODEV_FALSE
 MODULE_OSSAUDIODEV_TRUE
+MODULE__DATETIME_FALSE
+MODULE__DATETIME_TRUE
+MODULE_TIME_FALSE
+MODULE_TIME_TRUE
+MODULE__IO_FALSE
+MODULE__IO_TRUE
 TEST_MODULES
 LIBRARY_DEPS
 STATIC_LIBPYTHON
@@ -19456,45 +19462,48 @@ MODULE_BLOCK=
 
 
 
-# This is what autoupdate's m4 run will expand.  It fires
-# the warning (with _au_warn_XXX), outputs it into the
-# updated configure.ac (with AC_DIAGNOSE), and then outputs
-# the replacement expansion.
 
 
-# This is an auxiliary macro that is also run when
-# autoupdate runs m4.  It simply calls m4_warning, but
-# we need a wrapper so that each warning is emitted only
-# once.  We break the quoting in m4_warning's argument in
-# order to expand this macro's arguments, not AU_DEFUN's.
-
-
-# Finally, this is the expansion that is picked up by
-# autoconf.  It tells the user to run autoupdate, and
-# then outputs the replacement expansion.  We do not care
-# about autoupdate's warning because that contains
-# information on what to do *after* running autoupdate.
-
+     if true; then
+  MODULE__IO_TRUE=
+  MODULE__IO_FALSE='#'
+else
+  MODULE__IO_TRUE='#'
+  MODULE__IO_FALSE=
+fi
 
 
+    as_fn_append MODULE_BLOCK "MODULE__IO_CFLAGS='-I$(srcdir)/Modules/_io'$as_nl"
 
-    as_fn_append MODULE_BLOCK "MODULE_IO_CFLAGS=-I\$(srcdir)/Modules/_io$as_nl"
 
 
-    as_fn_append MODULE_BLOCK "MODULE_IO_LDFLAGS=$TIMEMODULE_LIB$as_nl"
 
+     if true; then
+  MODULE_TIME_TRUE=
+  MODULE_TIME_FALSE='#'
+else
+  MODULE_TIME_TRUE='#'
+  MODULE_TIME_FALSE=
+fi
 
 
 
+    as_fn_append MODULE_BLOCK "MODULE_TIME_LDFLAGS=$TIMEMODULE_LIB$as_nl"
 
 
-    as_fn_append MODULE_BLOCK "MODULE_TIME_LDFLAGS=$TIMEMODULE_LIB$as_nl"
 
 
+     if true; then
+  MODULE__DATETIME_TRUE=
+  MODULE__DATETIME_FALSE='#'
+else
+  MODULE__DATETIME_TRUE='#'
+  MODULE__DATETIME_FALSE=
+fi
 
 
 
-    as_fn_append MODULE_BLOCK "MODULE__DATETIME_LDFLAGS=$TIMEMODULE_LIB$as_nl"
+    as_fn_append MODULE_BLOCK "MODULE__DATETIME_LDFLAGS=$TIMEMODULE_LIB $LIBM$as_nl"
 
 
 
@@ -19871,6 +19880,18 @@ LTLIBOBJS=$ac_ltlibobjs
 
 
 
+if test -z "${MODULE__IO_TRUE}" && test -z "${MODULE__IO_FALSE}"; then
+  as_fn_error $? "conditional \"MODULE__IO\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${MODULE_TIME_TRUE}" && test -z "${MODULE_TIME_FALSE}"; then
+  as_fn_error $? "conditional \"MODULE_TIME\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${MODULE__DATETIME_TRUE}" && test -z "${MODULE__DATETIME_FALSE}"; then
+  as_fn_error $? "conditional \"MODULE__DATETIME\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${MODULE_OSSAUDIODEV_TRUE}" && test -z "${MODULE_OSSAUDIODEV_FALSE}"; then
   as_fn_error $? "conditional \"MODULE_OSSAUDIODEV\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
@@ -21111,7 +21132,7 @@ fi
 echo "creating Makefile" >&6
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local $srcdir/Modules/Setup.core $srcdir/Modules/Setup
+			Modules/Setup.local $srcdir/Modules/Setup.bootstrap $srcdir/Modules/Setup
 mv config.c Modules
 
 if test -z "$PKG_CONFIG"; then
diff --git a/configure.ac b/configure.ac
index 94c7a886913b6f..d9f50c3e8b9e3d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6035,8 +6035,7 @@ dnl PY_STDLIB_MOD_SIMPLE([NAME], [CFLAGS], [LDFLAGS])
 dnl cflags and ldflags are optional
 AC_DEFUN([PY_STDLIB_MOD_SIMPLE], [
   m4_pushdef([modcond], [MODULE_]m4_toupper([$1]))dnl
-  dnl _MODULE_BLOCK_ADD(modcond, [yes])
-  dnl AM_CONDITIONAL(modcond, [true])
+  AM_CONDITIONAL(modcond, [true])
   m4_ifval([$2], [
     _MODULE_BLOCK_ADD([MODULE_]m4_toupper([$1])[_CFLAGS], [$2])
   ])
@@ -6045,15 +6044,13 @@ AC_DEFUN([PY_STDLIB_MOD_SIMPLE], [
   ])
   m4_popdef([modcond])dnl
 ])
-dnl alias for static core modules (Modules/Setup.core)
-AU_ALIAS([PY_STDLIB_MOD_CORE], [PY_STDLIB_MOD_SIMPLE])
 
-dnl static modules in Modules/Setup.core
-PY_STDLIB_MOD_SIMPLE([io], [-I\$(srcdir)/Modules/_io], [$TIMEMODULE_LIB])
+dnl static modules in Modules/Setup.bootstrap
+PY_STDLIB_MOD_SIMPLE([_io], ['-I$(srcdir)/Modules/_io'], [])
+PY_STDLIB_MOD_SIMPLE([time], [], [$TIMEMODULE_LIB])
 
 dnl always enabled extension modules
-PY_STDLIB_MOD_SIMPLE([time], [], [$TIMEMODULE_LIB])
-PY_STDLIB_MOD_SIMPLE([_datetime], [], [$TIMEMODULE_LIB])
+PY_STDLIB_MOD_SIMPLE([_datetime], [], [$TIMEMODULE_LIB $LIBM])
 
 dnl platform specific extensions
 PY_STDLIB_MOD([ossaudiodev],
@@ -6087,7 +6084,7 @@ fi
 echo "creating Makefile" >&AS_MESSAGE_FD
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local $srcdir/Modules/Setup.core $srcdir/Modules/Setup
+			Modules/Setup.local $srcdir/Modules/Setup.bootstrap $srcdir/Modules/Setup
 mv config.c Modules
 
 if test -z "$PKG_CONFIG"; then
diff --git a/setup.py b/setup.py
index fb9fd2b498d55e..fc04efc77e19ed 100644
--- a/setup.py
+++ b/setup.py
@@ -1006,13 +1006,10 @@ def detect_simple_extensions(self):
         if lib:
             time_libs.append(lib)
 
-        # time operations and variables, always built by Modules/Setup.core
-        # self.add(Extension('time', ['timemodule.c'],
-        #                    libraries=time_libs))
+        # time module is built by Modules/Setup.bootstrap
         # libm is needed by delta_new() that uses round() and by accum() that
         # uses modf().
-        self.add(Extension('_datetime', ['_datetimemodule.c'],
-                           libraries=['m']))
+        self.addext(Extension('_datetime', ['_datetimemodule.c']))
         # zoneinfo module
         self.add(Extension('_zoneinfo', ['_zoneinfo.c']))
         # random number generator implemented in C
@@ -1034,8 +1031,7 @@ def detect_simple_extensions(self):
         self.add(Extension('_opcode', ['_opcode.c']))
         # asyncio speedups
         self.add(Extension("_asyncio", ["_asynciomodule.c"]))
-        # _abc speedups, always built by Modules/Setup.core
-        # self.add(Extension("_abc", ["_abc.c"]))
+        # _abc module is built by Modules/Setup.bootstrap
         # _queue module
         self.add(Extension("_queue", ["_queuemodule.c"]))
         # _statistics module
@@ -1054,8 +1050,7 @@ def detect_simple_extensions(self):
             libs = ['bsd']
         self.add(Extension('fcntl', ['fcntlmodule.c'],
                            libraries=libs))
-        # pwd(3), always built by Modules/Setup.core
-        # self.add(Extension('pwd', ['pwdmodule.c']))
+        # pwd module is built by Modules/Setup.bootstrap
         # grp(3)
         if not VXWORKS:
             self.add(Extension('grp', ['grpmodule.c']))

From e11c9b65ea7b4c16c3ac265424c24cec1bd34632 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Fri, 19 Nov 2021 10:22:45 +0100
Subject: [PATCH 3/5] Fix comment

---
 Modules/Setup | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/Setup b/Modules/Setup
index 54abb17a4fd711..5a7c232d3c555e 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -112,7 +112,7 @@ PYTHONPATH=$(COREPYTHONPATH)
 
 # ---
 # Built-in modules required to get a functioning interpreter are listed in
-# Modules/Setup.core.
+# Modules/Setup.bootstrap.
 
 # ---
 # The rest of the modules listed in this file are all commented out by

From e749a53c16573a9d516aaecf4f8307f7891ad8b1 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Fri, 19 Nov 2021 10:25:38 +0100
Subject: [PATCH 4/5] Single quotes don't work

---
 configure    | 2 +-
 configure.ac | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index 9d03d89a241ef4..96005cb63aff05 100755
--- a/configure
+++ b/configure
@@ -19473,7 +19473,7 @@ else
 fi
 
 
-    as_fn_append MODULE_BLOCK "MODULE__IO_CFLAGS='-I$(srcdir)/Modules/_io'$as_nl"
+    as_fn_append MODULE_BLOCK "MODULE__IO_CFLAGS=-I\$(srcdir)/Modules/_io$as_nl"
 
 
 
diff --git a/configure.ac b/configure.ac
index d9f50c3e8b9e3d..d4c9bef4242656 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6046,7 +6046,7 @@ AC_DEFUN([PY_STDLIB_MOD_SIMPLE], [
 ])
 
 dnl static modules in Modules/Setup.bootstrap
-PY_STDLIB_MOD_SIMPLE([_io], ['-I$(srcdir)/Modules/_io'], [])
+PY_STDLIB_MOD_SIMPLE([_io], [-I\$(srcdir)/Modules/_io], [])
 PY_STDLIB_MOD_SIMPLE([time], [], [$TIMEMODULE_LIB])
 
 dnl always enabled extension modules

From db3e45e1659767efc997c77c93f6c9611cfe3f94 Mon Sep 17 00:00:00 2001
From: Christian Heimes <christian@python.org>
Date: Fri, 19 Nov 2021 16:01:01 +0100
Subject: [PATCH 5/5] Consolidate comments about extensions in Setup.bootstrap

---
 setup.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/setup.py b/setup.py
index fc04efc77e19ed..0b7e7ab0a30613 100644
--- a/setup.py
+++ b/setup.py
@@ -1006,7 +1006,6 @@ def detect_simple_extensions(self):
         if lib:
             time_libs.append(lib)
 
-        # time module is built by Modules/Setup.bootstrap
         # libm is needed by delta_new() that uses round() and by accum() that
         # uses modf().
         self.addext(Extension('_datetime', ['_datetimemodule.c']))
@@ -1031,7 +1030,6 @@ def detect_simple_extensions(self):
         self.add(Extension('_opcode', ['_opcode.c']))
         # asyncio speedups
         self.add(Extension("_asyncio", ["_asynciomodule.c"]))
-        # _abc module is built by Modules/Setup.bootstrap
         # _queue module
         self.add(Extension("_queue", ["_queuemodule.c"]))
         # _statistics module
@@ -1050,7 +1048,6 @@ def detect_simple_extensions(self):
             libs = ['bsd']
         self.add(Extension('fcntl', ['fcntlmodule.c'],
                            libraries=libs))
-        # pwd module is built by Modules/Setup.bootstrap
         # grp(3)
         if not VXWORKS:
             self.add(Extension('grp', ['grpmodule.c']))
@@ -1505,6 +1502,9 @@ def detect_modules(self):
         self.configure_compiler()
         self.init_inc_lib_dirs()
 
+        # Some C extensions are built by entries in Modules/Setup.bootstrap.
+        # These are extensions are required to bootstrap the interpreter or
+        # build process.
         self.detect_simple_extensions()
         if TEST_EXTENSIONS:
             self.detect_test_extensions()