mail.mailutils gets to/from addresses wrong

[Richard Kettlewell]

If I submit mail with unqualified addresses directly...

    richard@lyonesse:~$ /usr/sbin/exim4 -t
    To: root
    Subject: test

    body
    richard@lyonesse:~$

...then the MTA qualifies them correctly:

    To: <email address hidden>
    Subject: test
    Message-Id: <E1dbPiV-0001g2-Ft@lyonesse>
    From: Richard Kettlewell <email address hidden>

However if I submit mail with mail.mailutils...

    richard@lyonesse:~$ mail -s test root < /dev/null
    mail: Null message body; hope that's ok
    richard@lyonesse:~$

...then it makes a bad guess at how to turn them into fully qualified addresses:

    To: <root@lyonesse>
    Message-Id: <E1dbPjb-0001h6-St@lyonesse>
    From: Richard Kettlewell <richard@lyonesse>

mail thinks it knows how to qualify email addresses, but it's wrong. Instead, it should leave it to the system MTA, which does know.

richard@lyonesse:~$ cat /etc/mailname
anjou.terraraq.uk
ichard@lyonesse:~$ ls -l /usr/bin/mail /etc/alternatives/mail
lrwxrwxrwx 1 root root 23 Jul 26 23:29 /etc/alternatives/mail -> /usr/bin/mail.mailutils
lrwxrwxrwx 1 root root 22 Jul 26 23:29 /usr/bin/mail -> /etc/alternatives/mail
richard@lyonesse:~$ lsb_release -rd
Description: Ubuntu 17.04
Release: 17.04
richard@lyonesse:~$ dpkg -l mailutils exim4\*
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-============-============-=================================
un exim4 <none> <none> (no description available)
ii exim4-base 4.88-5ubuntu amd64 support files for all Exim MTA (v
ii exim4-config 4.88-5ubuntu all configuration for the Exim MTA (v
un exim4-config-2 <none> <none> (no description available)
un exim4-daemon-c <none> <none> (no description available)
ii exim4-daemon-h 4.88-5ubuntu amd64 Exim MTA (v4) daemon with extende
un exim4-daemon-l <none> <none> (no description available)
ii exim4-doc-html 4.88-1 all documentation for the Exim MTA (v
un exim4-doc-info <none> <none> (no description available)
un exim4-localsca <none> <none> (no description available)
ii mailutils 1:3.1.1-1 amd64 GNU mailutils utilities for handl