Fixed warning.

diff --git a/dlls/ttydrv/ttydrv_main.c b/dlls/ttydrv/ttydrv_main.c
index 4141dc5..0c7f056 100644
--- a/dlls/ttydrv/ttydrv_main.c
+++ b/dlls/ttydrv/ttydrv_main.c
@@ -7,6 +7,7 @@
 #include <stdio.h>
 
 #include "winbase.h"
+#include "wine/winbase16.h"
 #include "clipboard.h"
 #include "gdi.h"
 #include "message.h"