Without this change, I get the following error (when installed with
stow under /usr/local/stow):

elmarco@pipo /usr/local/stow$ jhbuild buildone libtelepathy
I: unknown keys defined in configuration file: DATADIR
Traceback (most recent call last):
  File /usr/local/bin/jhbuild, line 28, in <module>
    jhbuild.main.main(sys.argv[1:])
  File /usr/local/stow/jhbuild/lib/python2.5/site-packages/jhbuild/main.py, line 145, in main
    rc = jhbuild.commands.run(command, config, args)
  File /usr/local/stow/jhbuild/lib/python2.5/site-packages/jhbuild/commands/__init__.py, line 78, in run
    return cmd.execute(config, args)
  File /usr/local/stow/jhbuild/lib/python2.5/site-packages/jhbuild/commands/__init__.py, line 44, in execute
    return self.run(config, options, args)
  File /usr/local/stow/jhbuild/lib/python2.5/site-packages/jhbuild/commands/base.py, line 405, in run
    check_bootstrap_updateness(config)
  File /usr/local/stow/jhbuild/lib/python2.5/site-packages/jhbuild/commands/base.py, line 200, in check_bootstrap_updateness
    bootstrap_mtime = os.stat(bootstrap_uri)[stat.ST_MTIME]
OSError: [Errno 2] No such file or directory: '/usr/local/lib/python2.5/site-packages/jhbuild/commands/../../modulesets/bootstrap.modules'

thanks,