Unfair handling of the situation where some player does not get some startunit
Jtn in https://www.hostedredmine.com/issues/767127, where we only avoid the fatal error:
"Not sure what should happen if we hit the bail-out. In other failure cases nearby in init_new_game(), the game silently drops that player's starting unit, which doesn't seem very fair (especially if that was the only city founder in the pack!); there's only a complaint if a player gets no units at all. Probably we should at least warn the player in all these cases, and maybe tell everyone and/or abort the game (although there's no abort code path here currently)."