Experimental patch and convenience utility.

So I ended up spending little bit more time hacking on your project. It started to look more like a fork rather than just some tweaks, which really wasn't the idea, so I cleaned everything up and put it in a script. This isn't really a 'pull request' proper (though by all means, merge anything you see that you like); I just thought it was the easiest way to show it to you, so you can close it whenever.

The basic idea was to see how close I could get it to 'bootstrap' with as much of a non-GPL (or at least non-Oracle) toolchain (and incidentally, automate some of the stuff in your readme). I'm to tired to detail everything at the moment but ping if anything doesn't make sense. Hope you find it interesting.

P.S. Nothing here is intended to be really Mac specific, and I speculatively wrote some parts for other platforms, but I haven't tested it on anything else. I did test all the shell snippets and the script itself in both bash and dash, so there's at least that.