We currently do something unusual: version codes in config.in get
updated after the release, which means that "git describe" won't
match up to development version labels. Comment that trouble spot.
We can fix this by switching away from the major/minor/micro type
release numbering, as various other projects have done. The major
numbers basically don't tend to change, and doing a good job with
micro versions is so annoying that they rarely change either.