https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108305
--- Comment #7 from Jonathan Wakely <redi at gcc dot gnu.org> --- I think we need to make __cpp_lib_ios_noreplace depend on some new macro that is undefined by default, and defined manually in os_defines.h when we know it works. The won't work for musl though, as it uses the generic os_defines.h
