Fix broken use of MsgWaitForMultipleObjects.

- Timeout < 0 was not handled properly
- Return value for success is WAIT_OBJECT_0 + nCount, not positive value

src/video/windows/SDL_windowsevents.c

@@ -1687,7 +1687,10 @@ void SDL_SetWindowsMessageHook(SDL_WindowsMessageHook callback, void *userdata)
 int WIN_WaitEventTimeout(SDL_VideoDevice *_this, Sint64 timeoutNS)
 {
     if (g_WindowsEnableMessageLoop) {
-        if (MsgWaitForMultipleObjects(0, NULL, FALSE, (DWORD)SDL_NS_TO_MS(timeoutNS), QS_ALLINPUT)) {
+        DWORD timeout, ret;
+        timeout = timeoutNS < 0 ? INFINITE : (DWORD)SDL_NS_TO_MS(timeoutNS);
+        ret = MsgWaitForMultipleObjects(0, NULL, FALSE, timeout, QS_ALLINPUT);
+        if (ret == WAIT_OBJECT_0) {
             return 1;
         } else {
             return 0;