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

windows/win.c

diff --git a/windows/win.c b/windows/win.c
index a7e0c4e..8225791 100644
--- a/windows/win.c
+++ b/windows/win.c
@@ -27,6 +27,7 @@
 #include "windef.h"
 #include "wine/winbase16.h"
 #include "wine/winuser16.h"
+#include "wownt32.h"
 #include "wine/server.h"
 #include "wine/unicode.h"
 #include "win.h"