Re: [Bug 3949] ALL_TRUSTED misfires when Received: parsing fails.

[Loren Wilton]

An alternate simple case to detect local mail delivery would be to count the
received headers, whether they can be parsed or not, and are trusted or not.
If #received-hdrs <= 1 and trusted==0 and untrusted==0, assume local
delivery and trust it.  Probably should be a configurable option if done at
all.