[PATCH] stdlib: Do not define once_flag, ONCE_FLAG_INIT for C++

[Florian Weimer]

* Jonathan Wakely:

>   @menu
>   * ISO C Threads Return Values:: Symbolic constants that represent a
>  @@ -203,11 +210,17 @@ called once in the presence of multiple, potentially calling threads.
>   @deftp {Data Type} once_flag
>   @standards{C11, threads.h}
>   A complete object type capable of holding a flag used by @code{call_once}.
>  +
>  +As of C23, @code{once_flags} is also defined in @file{stdlib.h},
>
> s/once_flags/once_flag/

Thanks, fixed locally.

Florian