[libcxx] Use C11 thread API on Fuchsia
authorPetr Hosek <phosek@google.com>
Wed, 4 Dec 2019 18:38:22 +0000 (10:38 -0800)
committerPetr Hosek <phosek@google.com>
Wed, 15 Jan 2020 00:48:20 +0000 (16:48 -0800)
commitab9aefee9fa09957d1a3e76fcc47abda0d002255
tree4367ff1c99516ed8240e8bd81b9e14b8d3addaef
parentc9ee5e996e3c89a751a35e8b771870e0ec24f3c0
[libcxx] Use C11 thread API on Fuchsia

On Fuchsia, pthread API is emulated on top of C11 thread API. Using C11
thread API directly is more efficient.

While this implementation is only used by Fuchsia at the moment, it's
not Fuchsia specific, and could be used by other platforms that use C11
threads rather than pthreads in the future.

Differential Revision: https://reviews.llvm.org/D64378
libcxx/include/__config
libcxx/include/__threading_support