Add bash git repo for HEAD compilation

I haven't tested what the patch fixed, and it doesn't [apply directly](https://www.youtube.com/watch?v=f_SwD7RveNE) to HEAD.

I don't know if that would be a blocker to being able to compile from HEAD, or if there should be a message printed for any bash HEAD installers.

I'm working on the latest bash from HEAD in my slackware machine, and wanted to get everything available on my OSX install.