Fixed wownt32.h to make it usable from inside Wine, and use it to
avoid some duplication of the handle conversion macros.

diff --git a/controls/menu.c b/controls/menu.c
index 52742a5..0470e80 100644
--- a/controls/menu.c
+++ b/controls/menu.c
@@ -39,6 +39,7 @@
 #include "wingdi.h"
 #include "wine/winbase16.h"
 #include "wine/winuser16.h"
+#include "wownt32.h"
 #include "wine/server.h"
 #include "wine/unicode.h"
 #include "win.h"