> It seems that the PLIST for mail/spamassassin misses some files?
> 
> $ pkg_info -F /usr/pkg/bin/spamassassin 
> pkg_info: No matching pkg for /usr/pkg/bin/spamassassin.
> 
> That's also true for spamc and other files in /usr/pkg/bin. They are
> also not present in the generated binary package that I have.

When you build it with pkgsrc, what is in your
work/Mail-SpamAssassin-3.1.4/auto/Mail/SpamAssassin/.packlist
and ${WRKSRC}/.PLIST* files?