Re: Cleanup initialization of configure process (issue 549350043 by jonas.hahnfeld@gmail.com)

[nine . fierce . ballads]

I've run some builds with a writable source directory, and I'm fine with
it.  Feel free to move forward with the cleaner change.  I'll submit a
LilyDev pull request to cope with it.

https://codereview.appspot.com/549350043/