[Bug c/71949] ATOMIC_FLAG_INIT definition in stdatomic.h

[patrick.pelissier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71949

--- Comment #2 from Patrick Pelissier <patrick.pelissier at gmail dot com> ---
I am not sure that DR#454 applies to this case as _Atomic types are allowed to
have additional state needed by the implementation to carry for the atomic
object (§7.17.2.2) whereas atomic_flag has only two states - set and clear -
(§7.17.8) and no potential additional state is mentioned for the atomic flag.
This would explain why the atomic_init generic function exists to initialize an
atomic, but there is no equivalent function for atomic_flag.