https://gitlab.freedesktop.org/xdg/startup-notification/-/work_items/6

Index: libmate-desktop/mate-desktop-item.c
--- libmate-desktop/mate-desktop-item.c.orig
+++ libmate-desktop/mate-desktop-item.c
@@ -1589,7 +1589,7 @@ startup_timeout (void *data)
 		suseconds_t tv_usec;
 		gint64 tv;
 
-		sn_launcher_context_get_last_active_time (sn_context, &tv_sec, &tv_usec);
+		sn_launcher_context_get_last_active_time (sn_context, (long *)&tv_sec, &tv_usec);
 		tv = (tv_sec * G_USEC_PER_SEC) + tv_usec;
 		elapsed = (double) (now - tv) / 1000.0;
 #else
