[libcxx] Use mtx_plain | mtx_recursive following C11 API
authorPetr Hosek <phosek@google.com>
Wed, 15 Jan 2020 21:58:29 +0000 (13:58 -0800)
committerPetr Hosek <phosek@google.com>
Wed, 15 Jan 2020 23:15:39 +0000 (15:15 -0800)
commit3481e5d7ed08d068a4e3427cb1afcd8bf2acafdc
tree57f6d06e2ded855df24238458bb5d85d417db38b
parent8045a8a7f184b682bfb4e729a986a3c2bd3a5b4e
[libcxx] Use mtx_plain | mtx_recursive following C11 API

The C11 API specifies that to initialize a recursive mutex,
mtx_plain | mtx_recursive should be used with mtx_init.

Differential Revision: https://reviews.llvm.org/D72809
libcxx/include/__threading_support