_Noreturn, just like __attribute__((noreturn)), is ignored.
I also added stdnoreturn.h, in all its glorious uselessness.
_Alignas only works for integer expressions right now. In order
to comply, we need:
- _Alignas(type) -> _Alignas(_Alignof(type)).
- stdalign.h as soon as it is done.
Note: DR 444 is supported; it works on struct members.
Signed-off-by: Devin Hussey <husseydevin@gmail.com>
