While that is true, Any solution is going to be a heuristic. There is literally no way to know what repo they are building against (if they are building against a Bukkit fork). I guess the right answer would be to try the following in order:

* [owner of CraftBukkit fork]/Bukkit
* [username]/Bukkit
* Bukkit/Bukkit

If you have any suggestions about determining the name of the Bukkit fork (in the case that it is not named "Bukkit" (and if it isn't, you're an asshole)), I would be interested in hearing them. I'm not sure how much useful info Travis provides through its ENV variables.