winuser.h now requires that we include winbase.h first.

diff --git a/windows/hook.c b/windows/hook.c
index 68ca4c1..a2b7ca7 100644
--- a/windows/hook.c
+++ b/windows/hook.c
@@ -15,6 +15,7 @@
  */
 
 #include "windef.h"
+#include "winbase.h"
 #include "wingdi.h"
 #include "winuser.h"
 #include "wine/winuser16.h"