import re


def extract_jobs_flags(arguments):
    """
    Extract make job flags from a list of other make flags, i.e. -j8 -l8.

    :param arguments: string of space separated arguments which may or may not
        contain make job flags
    :type arguments: str
    :returns: list of make jobs flags as a space separated string
    :rtype: str
    """
    regex = (
        r'(?:^|\s)(-?(?:j|l)(?:\s*[0-9]+|\s|$))'
        r'|'
        r'(?:^|\s)((?:--)?(?:jobs|load-average)(?:(?:=|\s+)[0-9]+|(?:\s|$)))'
    )
    matches = re.findall(regex, arguments) or []
    matches = [m[0] or m[1] for m in matches]
    return ' '.join([m.strip() for m in matches]) if matches else None