pased a year > 99. This change fixes the conversion of 2-digit years
into tm_year format.
This change is differs from the OpenBSD fix because of differences
in our assign_date().
PR: 15872
Reported by: "Crist J. Clark" <cjclark@home.com>
Submitted by: "Sergey N. Voronkov" <serg@dor.zaural.ru>
Obtained from: OpenBSD