Devin Carraway <qpsmtpd@devin.com>: Patch to not accept half mails if
the connection gets dropped at the wrong moment.  Support and enable
taint checking. MAIL FROM host dns check configurable.

Andrew Pam <xanni@glasswings.com.au>: fixing the maximum message size
(databytes) stuff.

Marius Kjeldahl <marius@kjeldahl.net>, Zukka Zitting
<jukka.zitting@iki.fi>: Patches for supporting $ENV{RELAYCLIENT}