Work around macOS header that has ‘#define __has_builtin(x) 0’
when compiled by GCC. Apple really, really doesn’t want you to
use GCC, apparently. Rroblem reported by Akim Demaille in:
https://lists.gnu.org/r/bug-bison/2019-10/msg00071.html
The fix is to not trust __has_builtin when being compiled by
recent-enough GCC.
* lib/intprops.h (__has_builtin)
(_GL_HAS___builtin_add_overflow, _GL_TEMPDEF___has_builtin):
* lib/verify.h (__has_builtin, _GL_HAS___builtin_unreachable)
(_GL_HAS___builtin_trap, _GL_TEMPDEF___has_builtin):
Remove. All uses removed.
* lib/intprops.h (_GL_HAS_BUILTIN_ADD_OVERFLOW): Use __has_builtin
directly, if defined and if not newer GCC.
* lib/verify.h (_GL_HAS_BUILTIN_TRAP, _GL_HAS_BUILTIN_UNREACHABLE):
New macro, that use __has_builtin directly, if defined and if
not newer GCC.
(assume): Use them.