[gcc r16-4034] libstdc++: Remove unwanted PACKAGE macros from c++config.h [PR79147]

[Jonathan Wakely]

https://gcc.gnu.org/g:1953939243e1ab8c839c1bcb2a072d1e84627afe

commit r16-4034-g1953939243e1ab8c839c1bcb2a072d1e84627afe
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Sep 19 12:11:26 2025 +0100

    libstdc++: Remove unwanted PACKAGE macros from c++config.h [PR79147]
    
    Autoconf insists on adding macros like PACKAGE_NAME and
    PACKAGE_BUG_TARNAME to config.h but those are useless for libstdc++
    because it's not a complete package, just a sub-directory of gcc, and we
    never use any of those strings in our sources.
    
    Since we include the generated config.h in our installed c++config.h
    header, those useless macros are exposed to users. We do transform them
    to use the reserved _GLIBCXX_ prefix, but they're still just useless
    noise in the installed header.
    
    I don't know any way to get autoconf to not add them to config.h but
    this change comments them out so they're not defined when users include
    our headers.
    
    Although not really important now that the macro isn't being defined,
    this change also avoids the double substitution for PACKAGE_VERSION
    which was resulting in _GLIBCXX_PACKAGE__GLIBCXX_VERSION.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/79147
            * include/Makefile.am (c++config.h): Adjust sed command to
            comment out all PACKAGE_XXX macros and to avoid adjusting
            PACKAGE_VERSION twice.
            * include/Makefile.in: Regenerate.

Diff:
---
 libstdc++-v3/include/Makefile.am | 4 ++--
 libstdc++-v3/include/Makefile.in | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index 0b0cbe2d3faf..d1e5c3d84918 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -1420,8 +1420,8 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 	-e "$$verbose_assert" \
 	    < ${glibcxx_srcdir}/include/bits/c++config > $@ ;\
 	sed -e 's/HAVE_/_GLIBCXX_HAVE_/g' \
-	    -e 's/PACKAGE/_GLIBCXX_PACKAGE/g' \
-	    -e 's/VERSION/_GLIBCXX_VERSION/g' \
+	    -e '/PACKAGE/s,^,// ,' \
+	    -e '/PACKAGE/!s/VERSION/_GLIBCXX_VERSION/g' \
 	    -e 's/WORDS_/_GLIBCXX_WORDS_/g' \
 	    -e 's/LT_OBJDIR/_GLIBCXX_LT_OBJDIR/g' \
 	    -e 's/STDC_HEADERS/_GLIBCXX_STDC_HEADERS/g' \
diff --git a/libstdc++-v3/include/Makefile.in b/libstdc++-v3/include/Makefile.in
index e3a6d5f13905..13c0b5b4f839 100644
--- a/libstdc++-v3/include/Makefile.in
+++ b/libstdc++-v3/include/Makefile.in
@@ -1897,8 +1897,8 @@ ${host_builddir}/c++config.h: ${CONFIG_HEADER} \
 	-e "$$verbose_assert" \
 	    < ${glibcxx_srcdir}/include/bits/c++config > $@ ;\
 	sed -e 's/HAVE_/_GLIBCXX_HAVE_/g' \
-	    -e 's/PACKAGE/_GLIBCXX_PACKAGE/g' \
-	    -e 's/VERSION/_GLIBCXX_VERSION/g' \
+	    -e '/PACKAGE/s,^,// ,' \
+	    -e '/PACKAGE/!s/VERSION/_GLIBCXX_VERSION/g' \
 	    -e 's/WORDS_/_GLIBCXX_WORDS_/g' \
 	    -e 's/LT_OBJDIR/_GLIBCXX_LT_OBJDIR/g' \
 	    -e 's/STDC_HEADERS/_GLIBCXX_STDC_HEADERS/g' \