* recognize whether strftime actually failed or just returned "".
*/
tmpbuf[0] = '\1';
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
tmplen = strftime (tmpbuf, tmpbufsize, locale_format, &tm);
#pragma GCC diagnostic pop
if (tmplen == 0 && tmpbuf[0] != '\0')
{