https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99995
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- Similarly, <semaphore> unconditionally includes POSIX <semaphore.h> even if we're not going to use it.
[Bug libstdc++/99995] [11/12 Regression] should not include in c++20 mode
redi at gcc dot gnu.org via Gcc-bugs Wed, 21 Apr 2021 05:06:12 -0700
