static inline const char*
__tm_to_tzname(const struct tm *tm)
{
        const void *p = tm->tm_zone;
        if (p)
                return p;
        if (tm->tm_gmtoff == timezone)
                return tzname[0];
        if (tm->tm_gmtoff == daylight)
                return tzname[1];
        if (tm->tm_gmtoff == 0)
                return "GMT";

        return "";
}

#define __tm_gmtoff tm_gmtoff
#define __tm_zone tm_zone