https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115797
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- I'll make this work again, but it's stupid code. If the file is being compiled as C++, then <math.h> etc. are C++ headers, so it's either redundant or incorrect to mess with the language linkage of their contents. It can only help for broken <math.h> headers that are not compatible with C++, but in that case the hacky workaround should be limited to systems where those headers are actually broken. Not applied unconditionally.
