GCC rejects ABI tags on non mangled functions, as they would otherwise
be a no-op. This commit replaces such instances with equivalent
_LIBCPP_HIDE_FROM_ABI constants but without ABI tags attached.
.../include/c++/v1/__support/musl/xlocale.h:28:68: error: 'abi_tag'
attribute applied to extern "C" declaration 'long long int
strtoll_l(const char*, char**, int, locale_t)'
28 | strtoll_l(const char *__nptr, char **__endptr, int __base, locale_t) {
| ^
Bug: https://bugs.gentoo.org/869038
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D142415
We do ship those headers, so the directory name should not be something
that can potentially conflict with user-defined directories.
Differential Revision: https://reviews.llvm.org/D95956