Most gmtime implementations return a NULL value when they
encounter an error (and this behavior is specified by ANSI C
and POSIX). FreeBSD's implementation, however, will simply
leave the "struct tm" untouched. Let's also recognize this
and convert it to a NULL (with this patch, t4212 should pass
on FreeBSD).
Reported-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
