[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/libcxxabi/src/fallback_malloc.cpp b/libcxxabi/src/fallback_malloc.cpp
index 7e356d9..1d6c380 100644
--- a/libcxxabi/src/fallback_malloc.cpp
+++ b/libcxxabi/src/fallback_malloc.cpp
@@ -33,10 +33,9 @@
// When POSIX threads are not available, make the mutex operations a nop
#ifndef _LIBCXXABI_HAS_NO_THREADS
-_LIBCPP_SAFE_STATIC
-static std::__libcpp_mutex_t heap_mutex = _LIBCPP_MUTEX_INITIALIZER;
+static _LIBCPP_CONSTINIT std::__libcpp_mutex_t heap_mutex = _LIBCPP_MUTEX_INITIALIZER;
#else
-static void* heap_mutex = 0;
+static _LIBCPP_CONSTINIT void* heap_mutex = 0;
#endif
class mutexor {
