When P0883R2 was initially implemented in D103769 #pragma clang deprecated didn't exist yet.
We also forgot to cleanup usages in libc++ itself.
This takes care of both.
Differential Revision: https://reviews.llvm.org/D115995
The library is always build using C++20 so these guards are not needed.
Reviewed By: #libc, Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D115644
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
This allows simplifying the implementation of barriers.
This is a re-commit of 1ac403bd14, which had to be reverted in
64a9c944fc because the minimum CMake version wasn't high enough.
Now that we've upgraded, we can do this.
Differential Revision: https://reviews.llvm.org/D75243
Louis Dionne