Added process_id_t and thread_it_t types to the server interface
instead of using void*, and removed a number of type casts.

diff --git a/windows/message.c b/windows/message.c
index c1431dd..5951bff 100644
--- a/windows/message.c
+++ b/windows/message.c
@@ -116,7 +116,7 @@
     SERVER_START_REQ( send_message )
     {
         req->type   = type;
-        req->id     = (void *)GetWindowThreadProcessId( msg->hwnd, NULL );
+        req->id     = GetWindowThreadProcessId( msg->hwnd, NULL );
         req->win    = msg->hwnd;
         req->msg    = msg->message;
         req->wparam = msg->wParam;