Get a -r### off of PKG-INFO Version in case this is an sdist of
    a subversion revision.

def get_pkg_info_revision():
    """
    Get a -r### off of PKG-INFO Version in case this is an sdist of
    a subversion revision.
    """
    warnings.warn("get_pkg_info_revision is deprecated.", EggInfoDeprecationWarning)
    if os.path.exists('PKG-INFO'):
        with io.open('PKG-INFO') as f:
            for line in f:
                match = re.match(r"Version:.*-r(\d+)\s*$", line)
                if match:
                    return int(match.group(1))
    return 0