a similar way to the way it can select messages from a given program.
Lines beginning with "+hostname" or "#+hostname" select messaes
from that hostname and lines beginning with "-hostname" or "#-hostname"
match messages not from that hostname.
There are some significant style issues left in the original program
selection code and the man page. This should be cleared up in some
later commits.
Reviewed by: sheldonh
Based on an original patch by: Bernd Walter <ticso@cicely8.cicely.de>
Man page stylist: sheldonh
a144588d15