https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88749
--- Comment #9 from Romain Geissler <romain.geissler at amadeus dot com> --- This may be some naive question, but if we are currently trying to build a libstdc++, shouldn't we assume there is no pre-existing libstdc++ and run the different checks in the configure script either with the C compiler (if indeed we never use C++) or with CXXFLAGS like -nodefaultlib ?