On Fri, 19 Sept 2025 at 14:17, Jonathan Wakely wrote: > > 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.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79147 for the diff that this produces for c++config.h
