[PATCH] libstdc++: Add missing free functions for atomic_flag [PR103934]

[Jonathan Wakely]

>+  inline void
>+  atomic_flag_wait_explicit(const atomic_flag* __a, bool __old,
>+               std::memory_order __m) noexcept

No need for the std:: qualification, and check the indentation.


> libstdc++-v3/ChangeLog:
>
>    PR103934

This needs to include the component: PR libstdc++/103934

>    * include/std/atomic: Add missing free functions.

Please name the new functions in the changelog, in the usual format.
Just the names is fine, no need for the full signatures with
parameters.

OK for trunk with those changes.