util: use dllexport for mingw too

Acked-by: Jose Fonseca <jfonsec@vmware.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7341>

src/util/macros.h

@@ -219,12 +219,12 @@ do {                       \
  * inline a static function that we later use in an alias. - ajax
  */
 #ifndef PUBLIC
-#  if defined(__GNUC__)
-#    define PUBLIC __attribute__((visibility("default")))
-#    define USED __attribute__((used))
-#  elif defined(_MSC_VER)
+#  if defined(_WIN32)
 #    define PUBLIC __declspec(dllexport)
 #    define USED
+#  elif defined(__GNUC__)
+#    define PUBLIC __attribute__((visibility("default")))
+#    define USED __attribute__((used))
 #  else
 #    define PUBLIC
 #    define USED