[libc++] Rename *SAFE_STATIC to *CONSTINIT, and normalize its uses.
In src/, most files can use `constinit` directly because they're always
compiled with C++20. But some files, like "libcxxabi/src/fallback_malloc.cpp",
can't, because they're `#include`d directly from test cases in libcxxabi/test/
and therefore must (currently) compile as C++03. We might consider refactoring
those offending tests, or at least marking them `UNSUPPORTED: c++03`.
Differential Revision: https://reviews.llvm.org/D119264
diff --git a/libcxx/src/mutex.cpp b/libcxx/src/mutex.cpp
index d6758fb..6669e76 100644
--- a/libcxx/src/mutex.cpp
+++ b/libcxx/src/mutex.cpp
@@ -196,8 +196,8 @@
// keep in sync with: 7741191.
#ifndef _LIBCPP_HAS_NO_THREADS
-_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
-_LIBCPP_SAFE_STATIC static __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
+static constinit __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
+static constinit __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
#endif
void __call_once(volatile once_flag::_State_type& flag, void* arg,
