mi2mu version control

[John Sankey]

I have a set of programs to filter mi2mu output, and would like to
keep lilypond updating separate from mi2mu - one set of problems at a
time! Is it possible to keep the two separate, by saving/restoring or
marking read-only the files on which mi2mu depends or some other
simple means? If so, what files does mi2mu need?

John