The following are my (happy) Mail-SpamAssassin-3.2.5 installation observations.
Seen at untarring: Please make files dates reflect when they were last changed. Not all just 2008-06-10. We see checking module dependencies and their versions... NOTE: the optional Mail::SPF module is not installed... Please say if these are Perl modules or SpamAssassin modules or Cpan Perl modules, etc., even if you say so in README, etc. After the first of perl Makefile.PL PREFIX=$HOME && make && make install we expect cheery messages, "Good boy, looks good", well, at least the latter two don't bomb out :-) (Anyway, still accruing debris of older versions and older sa-updates in the file tree.)
