https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115735
--- Comment #6 from Sam James <sjames at gcc dot gnu.org> --- (In reply to Sam James from comment #4) > [...] ... another issue is how we handle extensions (non-standard functions; may behave differently across impls), or where glibc might say something is safe as an extension. See also https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115724#c2.