commit 91f07a370ccb331c4f4bb964a8c5fd63ced4d318
author Louis Dionne <ldionne.2@gmail.com> Tue Jan 19 13:04:01 2021 -0500
committer Copybara-Service <copybara-worker@google.com> Fri Feb 05 01:27:45 2021 -0800
tree 24d0f498854401c15c85ce852656766c37d337f8
parent 9361ee257538c69e2fbed1ea27e5bb30243f9702

[libc++] Make feature-test macros consistent with availability macros

Before this patch, feature-test macros didn't take special availability
markup into account, which means that feature-test macros can sometimes
appear to "lie". For example, if you compile in C++20 mode and target
macOS 10.13, the __cpp_lib_filesystem feature-test macro will be provided
even though the <filesystem> declarations are marked as unavailable.
This patch fixes that.

rdar://68142369

Differential Revision: https://reviews.llvm.org/D94983

GitOrigin-RevId: 76fc35752d19ac605c1c1fd757af9c7c3bb4a906