(hopefully) fixed iso8601 parser. Should work in GNU/Linux systems now, at least.

parseiso8601utc2.c

/*  parses only YYYY-MM-DDTHH:MM:SSZ */
time_t
parseiso8601utc_fixed(const char *date)
{
        struct tm tt = {0};
        double seconds;
        if (sscanf(date, "%04d-%02d-%02dT%02d:%02d:%lfZ",
                   &tt.tm_year, &tt.tm_mon, &tt.tm_mday,
                   &tt.tm_hour, &tt.tm_min, &seconds) != 6)
                return -1;
        tt.tm_year -= 1900;
        tt.tm_isdst = 0;
        tt.tm_sec = (int)seconds;
        tt.tm_mon--;
        return timegm(&tt);
}