[libc++] Refactor the configuration macros to being always defined (#112094)
This is a follow-up to #89178. This updates the `<__config_site>`
macros.
diff --git a/libcxx/src/memory_resource.cpp b/libcxx/src/memory_resource.cpp
index 3d0d4ea..0cd575e 100644
--- a/libcxx/src/memory_resource.cpp
+++ b/libcxx/src/memory_resource.cpp
@@ -12,7 +12,7 @@
#if _LIBCPP_HAS_ATOMIC_HEADER
# include <atomic>
-#elif !defined(_LIBCPP_HAS_NO_THREADS)
+#elif _LIBCPP_HAS_THREADS
# include <mutex>
# if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
# pragma comment(lib, "pthread")
@@ -101,7 +101,7 @@
} else {
return std::atomic_load_explicit(&__res, memory_order_acquire);
}
-#elif !defined(_LIBCPP_HAS_NO_THREADS)
+#elif _LIBCPP_HAS_THREADS
static constinit memory_resource* res = &res_init.resources.new_delete_res;
static mutex res_lock;
if (set) {
