def realpath(path):
    """
    Create the real absolute path for the given path.

    Add supports for userdir & / supports.

    Args:
        * path: pathname to use for realpath.

    Returns:
        Platform independent real absolute path.
    """
    if path == '~':
        return userdir

    if path == '/':
        return sysroot

    if path.startswith('/'):
        return os.path.abspath(path)

    if path.startswith('~/'):
        return os.path.expanduser(path)

    if path.startswith('./'):
        return os.path.abspath(os.path.join(os.path.curdir, path[2:]))

    return os.path.abspath(path)