[libcxx-commits] [libcxx] [libc++][modules] Add using_if_exists attribute (#77559) (PR #78909)

[Louis Dionne via libcxx-commits]

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@@ -16,10 +16,10 @@ export {
   // [support.start.term], start and termination
   using ::_Exit;
   using ::abort;
-  using ::at_quick_exit;
+  using ::at_quick_exit _LIBCPP_USING_IF_EXISTS;
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ldionne wrote:

@mordante We should really be using it for all C declarations we import. That would be required to work with libraries that e.g. don't provide support for localization and other similar things.

https://github.com/llvm/llvm-project/pull/78909