https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61532
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Marc Glisse from comment #4) > Writing "signed wchar_t" doesn't seem legal to me, and clang and intel warn > or reject such code. Yeah, it's a GCC extension, and I thought I'd replaced the uses of it in the tests with something portable, but apparently not!