[3.11] gh-98707: configure --with-system-libmpdec and --with-system-expat no longer include vendored headers (GH-98711) (#99391)

(cherry picked from commit 6abec1caffdba2e282b14fe57c6ce61974de4bbe)

Co-authored-by: Miro Hrončok <miro@hroncok.cz>

4 files changed, 11 insertions, 7 deletions

diff --git a/Makefile.pre.in b/Makefile.pre.in
index 17466c91b3b..b356f6293e6 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -2528,12 +2528,12 @@ Python/thread.o: @THREADHEADERS@ $(srcdir)/Python/condvar.h
 
 MODULE_CMATH_DEPS=$(srcdir)/Modules/_math.h
 MODULE_MATH_DEPS=$(srcdir)/Modules/_math.h
-MODULE_PYEXPAT_DEPS=$(LIBEXPAT_HEADERS) @LIBEXPAT_INTERNAL@
+MODULE_PYEXPAT_DEPS=@LIBEXPAT_INTERNAL@
 MODULE_UNICODEDATA_DEPS=$(srcdir)/Modules/unicodedata_db.h $(srcdir)/Modules/unicodename_db.h
 MODULE__BLAKE2_DEPS=$(srcdir)/Modules/_blake2/impl/blake2-config.h $(srcdir)/Modules/_blake2/impl/blake2-impl.h $(srcdir)/Modules/_blake2/impl/blake2.h $(srcdir)/Modules/_blake2/impl/blake2b-load-sse2.h $(srcdir)/Modules/_blake2/impl/blake2b-load-sse41.h $(srcdir)/Modules/_blake2/impl/blake2b-ref.c $(srcdir)/Modules/_blake2/impl/blake2b-round.h $(srcdir)/Modules/_blake2/impl/blake2b.c $(srcdir)/Modules/_blake2/impl/blake2s-load-sse2.h $(srcdir)/Modules/_blake2/impl/blake2s-load-sse41.h $(srcdir)/Modules/_blake2/impl/blake2s-load-xop.h $(srcdir)/Modules/_blake2/impl/blake2s-ref.c $(srcdir)/Modules/_blake2/impl/blake2s-round.h $(srcdir)/Modules/_blake2/impl/blake2s.c $(srcdir)/Modules/_blake2/blake2module.h $(srcdir)/Modules/hashlib.h
 MODULE__CTYPES_DEPS=$(srcdir)/Modules/_ctypes/ctypes.h
-MODULE__DECIMAL_DEPS=$(srcdir)/Modules/_decimal/docstrings.h $(LIBMPDEC_HEADERS) @LIBMPDEC_INTERNAL@
-MODULE__ELEMENTTREE_DEPS=$(srcdir)/Modules/pyexpat.c $(LIBEXPAT_HEADERS) @LIBEXPAT_INTERNAL@
+MODULE__DECIMAL_DEPS=$(srcdir)/Modules/_decimal/docstrings.h @LIBMPDEC_INTERNAL@
+MODULE__ELEMENTTREE_DEPS=$(srcdir)/Modules/pyexpat.c @LIBEXPAT_INTERNAL@
 MODULE__HASHLIB_DEPS=$(srcdir)/Modules/hashlib.h
 MODULE__IO_DEPS=$(srcdir)/Modules/_io/_iomodule.h
 MODULE__MD5_DEPS=$(srcdir)/Modules/hashlib.h
diff --git a/Misc/NEWS.d/next/Build/2022-10-26-12-37-52.gh-issue-98707.eVXGEx.rst b/Misc/NEWS.d/next/Build/2022-10-26-12-37-52.gh-issue-98707.eVXGEx.rst
new file mode 100644
index 00000000000..69afa9dea30
--- /dev/null
+++ b/Misc/NEWS.d/next/Build/2022-10-26-12-37-52.gh-issue-98707.eVXGEx.rst
@@ -0,0 +1,4 @@
+Don't use vendored ``libmpdec`` headers if :option:`--with-system-libmpdec`
+is passed to :program:`configure`.
+Don't use vendored ``libexpat`` headers if :option:`--with-system-expat`
+is passed to :program:`!configure`.
diff --git a/configure b/configure
index 2d5be29abf1..cb8eb0d3fb2 100755
--- a/configure
+++ b/configure
@@ -12110,7 +12110,7 @@ else
 
   LIBEXPAT_CFLAGS="-I\$(srcdir)/Modules/expat"
   LIBEXPAT_LDFLAGS="-lm \$(LIBEXPAT_A)"
-  LIBEXPAT_INTERNAL="\$(LIBEXPAT_A)"
+  LIBEXPAT_INTERNAL="\$(LIBEXPAT_HEADERS) \$(LIBEXPAT_A)"
 
 fi
 
@@ -12184,7 +12184,7 @@ else
 
   LIBMPDEC_CFLAGS="-I\$(srcdir)/Modules/_decimal/libmpdec"
   LIBMPDEC_LDFLAGS="-lm \$(LIBMPDEC_A)"
-  LIBMPDEC_INTERNAL="\$(LIBMPDEC_A)"
+  LIBMPDEC_INTERNAL="\$(LIBMPDEC_HEADERS) \$(LIBMPDEC_A)"
 
     if test "x$with_pydebug" = xyes; then :
 
diff --git a/configure.ac b/configure.ac
index 2cce5fe008d..948fd36aa80 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3610,7 +3610,7 @@ AS_VAR_IF([with_system_expat], [yes], [
 ], [
   LIBEXPAT_CFLAGS="-I\$(srcdir)/Modules/expat"
   LIBEXPAT_LDFLAGS="-lm \$(LIBEXPAT_A)"
-  LIBEXPAT_INTERNAL="\$(LIBEXPAT_A)"
+  LIBEXPAT_INTERNAL="\$(LIBEXPAT_HEADERS) \$(LIBEXPAT_A)"
 ])
 
 AC_SUBST([LIBEXPAT_CFLAGS])
@@ -3666,7 +3666,7 @@ AS_VAR_IF([with_system_libmpdec], [yes], [
 ], [
   LIBMPDEC_CFLAGS="-I\$(srcdir)/Modules/_decimal/libmpdec"
   LIBMPDEC_LDFLAGS="-lm \$(LIBMPDEC_A)"
-  LIBMPDEC_INTERNAL="\$(LIBMPDEC_A)"
+  LIBMPDEC_INTERNAL="\$(LIBMPDEC_HEADERS) \$(LIBMPDEC_A)"
 
   dnl Disable forced inlining in debug builds, see GH-94847
   AS_VAR_IF([with_pydebug], [yes], [