[Support] [Windows] Silence warnings about anonymous unions (#188534)
When building in mingw mode with Clang, we currently get the
following warnings:
llvm-project/llvm/lib/Support/Windows/Path.inc:1720:5: warning: anonymous types declared in an anonymous union are an extension [-Wnested-anon-types]
1720 | struct {
| ^
llvm-project/llvm/lib/Support/Windows/Path.inc:1728:5: warning: anonymous types declared in an anonymous union are an extension [-Wnested-anon-types]
1728 | struct {
| ^
Since these declarations mirror parts of the Microsoft SDKs, we
don't want to deviate from it needlessly; instead add a pragma
to silence this diagnostic for this specific area.
llvm-project
acef4cc2 - [Support] [Windows] Silence warnings about anonymous unions (#188534)
