Moved all Win16 definitions out of the standard Windows headers.

diff --git a/include/toolhelp.h b/include/toolhelp.h
index 735c4bb..c85f4aa 100644
--- a/include/toolhelp.h
+++ b/include/toolhelp.h
@@ -2,6 +2,7 @@
 #define __WINE_TOOLHELP_H
 
 #include "windef.h"
+#include "wine/windef16.h"
 
 #define MAX_DATA	11
 #define MAX_MODULE_NAME	9