t / t5100 / info0011on commit sequencer.c: teach append_signoff how to detect duplicate s-o-b (bab4d10)
   1Author: A U Thor
   2Email: a.u.thor@example.com
   3Subject: Xyzzy
   4Date: Fri, 8 Aug 2008 13:08:37 +0200 (CEST)
   5