[libcxx-commits] [libcxx] [libc++] Enable C++ stdatomic.h for all C++ versions (PR #95498)

[Ryan Prichard via libcxx-commits]

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@@ -154,10 +154,14 @@ using std::atomic_long _LIBCPP_USING_IF_EXISTS;
 using std::atomic_ulong _LIBCPP_USING_IF_EXISTS;
 using std::atomic_llong _LIBCPP_USING_IF_EXISTS;
 using std::atomic_ullong _LIBCPP_USING_IF_EXISTS;
+#  ifndef _LIBCPP_HAS_NO_CHAR8_T
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rprichard wrote:

It looks like GCC doesn't have the `__using_if_exists__` attribute, so the `generic-gcc-cxx11` test failed until I added the `#if`.

https://github.com/llvm/llvm-project/pull/95498