bpo-45573: Add Modules/Setup.stdlib with conditional modules

Signed-off-by: Christian Heimes <christian@python.org>

Author: tiran

.gitignore

@@ -76,6 +76,7 @@ Misc/python-embed.pc
 Misc/python-config.sh
 Modules/Setup.config
 Modules/Setup.local
+Modules/Setup.stdlib
 Modules/config.c
 Modules/ld_so_aix
 Programs/_freeze_module

Makefile.pre.in

@@ -898,11 +898,19 @@ oldsharedmods: $(SHAREDMODS) pybuilddir.txt
 		fi; \
 	done
 
+Modules/Setup.local:
+	@# Create empty Setup.local when file was deleted by user
+	echo "# Edit this file for local setup changes" > $@
+
+Modules/Setup.stdlib: $(srcdir)/Modules/Setup.stdlib.in config.status
+	./config.status $@
+
 Makefile Modules/config.c: Makefile.pre \
 				$(srcdir)/Modules/config.c.in \
 				$(MAKESETUP) \
 				$(srcdir)/Modules/Setup \
-				Modules/Setup.local
+				Modules/Setup.local \
+				Modules/Setup.stdlib
 	$(SHELL) $(MAKESETUP) -c $(srcdir)/Modules/config.c.in \
 				-s Modules \
 				Modules/Setup.local \

Misc/NEWS.d/next/Build/2021-11-18-12-18-43.bpo-45573.xsMZzn.rst

@@ -0,0 +1,2 @@
+``configure`` now creates ``Modules/Setup.stdlib`` with conditionally
+enabled/disabled extension module lines. The file is not used, yet.

Modules/Setup.stdlib.in

@@ -0,0 +1,55 @@
+# -*- makefile -*-
+#
+# This file is autogenerated from Modules/Setup.stdlib.in.
+#
+
+# The file is not used by default yet. For testing do:
+#
+#     ln -sfr Modules/Setup.stdlib Modules/Setup.local
+#
+
+# * @MODULE_{NAME}_TRUE@ is removed when configure detects all build
+#   dependencies for a module. Otherwise the template variable is replaced
+#   by a comment "#" and the module is skipped.
+# * Module lines without any compiler and linker flags automatically use
+#   $(MODULE_{NAME}_CFLAGS) and $(MODULE_{NAME}_LDFLAGS). These flags are
+#   generated by PY_STDLIB_MOD macro. 
+# * All source files automatically depend on $(PYTHON_HEADERS) and
+#   $(MODULE_{NAME}_DEPS).
+#
+# See Modules/Setup and Modules/makesetup
+#
+
+
+# Build modules statically or as shared extensions
+*shared*
+# *static*
+
+
+############################################################################
+# Modules that should always be present (POSIX and Windows):
+
+# _decimal uses libmpdec
+# either static libmpdec.a from Modules/_decimal/libmpdec or libmpdec.so
+# with ./configure --with-system-libmpdec
+@MODULE__DECIMAL_TRUE@_decimal _decimal/_decimal.c
+
+
+############################################################################
+# XML and text
+
+# pyexpat module uses libexpat
+# either static libexpat.a from Modules/expat or libexpat.so with
+# ./configure --with-system-expat
+@MODULE_PYEXPAT_TRUE@pyexpat pyexpat.c
+
+# _elementtree libexpat via CAPI hook in pyexpat.
+@MODULE__ELEMENTTREE_TRUE@_elementtree _elementtree.c
+
+
+############################################################################
+# Modules with some UNIX dependencies
+#
+
+# Linux and FreeBSD, needs sys/soundcard.h or linux/soundcard.h
+@MODULE_OSSAUDIODEV_TRUE@ossaudiodev ossaudiodev.c

configure

@@ -19437,6 +19437,8 @@ $as_echo "$py_cv_module__decimal" >&6; }
 # generate output files
 ac_config_files="$ac_config_files Makefile.pre Misc/python.pc Misc/python-embed.pc Misc/python-config.sh"
 
+ac_config_files="$ac_config_files Modules/Setup.stdlib"
+
 ac_config_files="$ac_config_files Modules/ld_so_aix"
 
 cat >confcache <<\_ACEOF
@@ -20172,6 +20174,7 @@ do
     "Misc/python.pc") CONFIG_FILES="$CONFIG_FILES Misc/python.pc" ;;
     "Misc/python-embed.pc") CONFIG_FILES="$CONFIG_FILES Misc/python-embed.pc" ;;
     "Misc/python-config.sh") CONFIG_FILES="$CONFIG_FILES Misc/python-config.sh" ;;
+    "Modules/Setup.stdlib") CONFIG_FILES="$CONFIG_FILES Modules/Setup.stdlib" ;;
     "Modules/ld_so_aix") CONFIG_FILES="$CONFIG_FILES Modules/ld_so_aix" ;;
 
   *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;

configure.ac

@@ -6005,6 +6005,7 @@ AC_SUBST([MODULE_BLOCK])
 
 # generate output files
 AC_CONFIG_FILES(Makefile.pre Misc/python.pc Misc/python-embed.pc Misc/python-config.sh)
+AC_CONFIG_FILES([Modules/Setup.stdlib])
 AC_CONFIG_FILES([Modules/ld_so_aix], [chmod +x Modules/ld_so_aix])
 AC_OUTPUT