x11: Removed an assert. This assert triggers when run under XMonad. It's safe to pass a zero here anyhow, as this will still work "well enough" and the original problem--GNOME printing a warning message--is still fixed because GNOME's window manager gives us a chance to grab a non-zero user-time value before this code is run.
diff --git a/src/video/x11/SDL_x11window.c b/src/video/x11/SDL_x11window.c
index 8856f7b..d798ab2 100644
--- a/src/video/x11/SDL_x11window.c
+++ b/src/video/x11/SDL_x11window.c
@@ -1047,7 +1047,6 @@ SetWindowActive(_THIS, SDL_Window * window)
if (X11_IsWindowMapped(_this, window)) {
XEvent e;
- SDL_assert(data->user_time != 0); /* should be set by _some_ event by now. */
/*printf("SDL Window %p: sending _NET_ACTIVE_WINDOW with timestamp %lu\n", window, data->user_time);*/
SDL_zero(e);