[Mimedefang] Adding filter_helo support

[Gary Funck]

> 
> Philip wanted an opportunity from MIMEDefang to change how Sendmail
> reacts to the HELO/EHLO command.  Right now, you can't; you have to wait
> for MAIL FROM: to do anything based on the HELO argument.
> 

OK, and what about the question raised as to how incoming mailers
might react if, for example, tempfailed at HELO time, and related
questions?