[clang] [Clang] Allow simpler visibility annotations when targeting win32 and mingw (PR #133699)

[Tomohiro Kashiwada via cfe-commits]

kikairoya wrote:

> Building libc++ with GCC is tested and supported on Linux. In MinGW environments it should probably work but it's not continuously tested. But iirc @kikairoya did test it quite recently?

AFAIK, building libc++ with MinGW-GCC requires a tweak ( a workaround for lacking `aligned_alloc` ) https://github.com/llvm/llvm-project/pull/141040#issuecomment-2906368661 , an extra linker option `-Wl,--export-all-symbols` ( unless #141040 ) https://github.com/llvm/llvm-project/pull/141040#issuecomment-2962416425 , and linking with LLD ( since BFD ld can't export weak symbols ) https://github.com/llvm/llvm-project/issues/135910#issuecomment-2888116112 .


https://github.com/llvm/llvm-project/pull/133699