Currently, all four manpages contain @Date@ and or @Version@,
see the output of grep -E '@(date|version)' *.8{,.in}.

This shouldn't be there in the first place: a date is a part of the manpage itself,
to be changed whenever someone changes the manpage; and nobody needs
two versions of the same manpage installed.

Makefile creates *.8 from *.8.in by sed'ing the @variables@;
but rather than adding @Date@ and @Version@ to the list,
let's please remove these from the manpages.