def get_flag(var, fallback, expected=True, warn=True):
    """Use a fallback value for determining SOABI flags if the needed config
    var is unset or unavailable."""
    val = get_config_var(var)
    if val is None:
        if warn:
            warnings.warn("Config variable '{0}' is unset, Python ABI tag may "
                          "be incorrect".format(var), RuntimeWarning, 2)
        return fallback
    return val == expected
Use a fallback value for determining SOABI flags if the needed config
    var is unset or unavailable.
product/gradle-plugin/src/main/python/wheel/bdist_wheel.py