Upgrade to the latest version of mingw-w64

This version includes the windows api sets version of the universal
crt, fixes a few other functions when used with the universal crt,
and fixes the widl tool when running on macos.

build-mingw-w64.sh

@@ -21,7 +21,7 @@ cd mingw-w64
 
 if [ -n "$SYNC" ] || [ -n "$CHECKOUT" ]; then
     [ -z "$SYNC" ] || git fetch
-    git checkout 95d6af0653895f962d797b3181b84b44340e6ef9
+    git checkout 5c9db71d0a5add53fd6d9cda0af7a7d470b8c596
 fi
 
 cd mingw-w64-headers