Don't warn about missing CTF starts if the gametype doesn't have team flags.

src/g_game.c

@@ -2720,7 +2720,7 @@ mapthing_t *G_FindCTFStart(INT32 playernum)
 
 	if (!numredctfstarts && !numbluectfstarts) //why even bother, eh?
 	{
-		if (playernum == consoleplayer || (splitscreen && playernum == secondarydisplayplayer))
+		if ((gametyperules & GTR_TEAMFLAGS) && (playernum == consoleplayer || (splitscreen && playernum == secondarydisplayplayer)))
 			CONS_Alert(CONS_WARNING, M_GetText("No CTF starts in this map!\n"));
 		return NULL;
 	}