Some more fixes for compiling the user dll with -DSTRICT.

diff --git a/windows/message.c b/windows/message.c
index 6ed668f..581eed2 100644
--- a/windows/message.c
+++ b/windows/message.c
@@ -778,7 +778,7 @@
 DWORD WINAPI WaitForInputIdle( HANDLE hProcess, DWORD dwTimeOut )
 {
     DWORD start_time, elapsed, ret;
-    HANDLE idle_event = -1;
+    HANDLE idle_event = (HANDLE)-1;
 
     SERVER_START_REQ( wait_input_idle )
     {