- maildrop: a message without a body, and without a blank line that
separates the message's headers from its body wasn't being parsed correctly.
This did not affect Courier which always inserts a blank line after headers,
even if a received message didn't have one.
- Add Received-SPF: headers for the message envelope sender before the first
Received: header. The Received-SPF: header for the HELO domain, if enabled,
wasn't being added to the message due to a bug.