def read_config():
    """Read configuration from setup.cfg."""
    # XXX modifies global state, which is kind of evil
    config = ConfigParser.ConfigParser()
    config.read(['setup.cfg'])
    if not config.has_section('check-manifest'):
        return
    if (config.has_option('check-manifest', 'ignore-default-rules')
            and config.getboolean('check-manifest', 'ignore-default-rules')):
        del IGNORE[:]
    if config.has_option('check-manifest', 'ignore'):
        patterns = [p.strip() for p in config.get('check-manifest',
                                                  'ignore').splitlines()]
        IGNORE.extend(p for p in patterns if p)
Read configuration from setup.cfg.