qmail doesn't *need* any patches

FWIW, I didn't mean 'built on Apache' as in 'runs as part of an Apache HTTPD'; Apache is in
part a very nice framework for writing generic server apps these days.  (Maybe this is
technically part of APR, I haven't followed where exactly they're drawing that boundary.)

On a further look, though, I see that you're right, when qpsmtpd is not running under httpd,
it uses a different home-brew network framework rather than APR.  I was misled by looking at
the first anti-malware plugin linked on their homepage:
  http://svn.perl.org/qpsmtpd/trunk/plugins/check_earlytalker
which contains a bunch of code using APR -- but it turns out that's because there are two
copies of all that code, one that works when being run under Apache and one that works with
the home-brew.  I don't know how typical this is of qpsmtpd's codebase, but it doesn't strike
me as The DJB Way either.

(If I were them, I'd consider just using Apache in all cases, even if it is a big hunk of
scary C that makes baby DJB cry, but I don't actually know what I'm talking about so *shrug*.)