xwayland: declare fatal log handler as noreturn

xwayland.c:661:1: warning: function 'xwl_log_handler' could be declared with
attribute 'noreturn' [-Wmissing-noreturn]

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

hw/xwayland/xwayland.c

@@ -656,6 +656,7 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
     return ret;
 }
 
+_X_NORETURN
 static void _X_ATTRIBUTE_PRINTF(1, 0)
 xwl_log_handler(const char *format, va_list args)
 {