[libcxx-commits] [libcxx] [libcxx] [test] Detect mingw-w64 headers compatible with C++ module builds (PR #92893)

[Jacek Caban via libcxx-commits]

cjacek wrote:

This looks correct, but if we need to check `__mingw_static_ovr` anyway, I wonder if `__MINGW64_VERSION_MAJOR` checks could be just skipped. 

https://github.com/llvm/llvm-project/pull/92893