[libcxx-commits] [libcxx] [libc++] Fix C++23 standard modules when using with `clang-cl` on Windows (PR #148992)

[Louis Dionne via libcxx-commits]

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@@ -14,15 +14,17 @@ export {
 
   using ::timespec _LIBCPP_USING_IF_EXISTS;
   using ::tm _LIBCPP_USING_IF_EXISTS;
-
   using ::asctime _LIBCPP_USING_IF_EXISTS;
   using ::clock _LIBCPP_USING_IF_EXISTS;
+  using ::strftime _LIBCPP_USING_IF_EXISTS;
+
+#ifndef _LIBCPP_ABI_VCRUNTIME
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ldionne wrote:

The `_LIBCPP_USING_IF_EXISTS` attribute is intended to make things work when the declarations are not available, and avoid precisely these `#ifdef` blocks. What's the issue here?

https://github.com/llvm/llvm-project/pull/148992