[Dovecot] when/where to set MAIL env variable?

[Mike Brown]

I am trying to get dovecot to work on a system that uses qmail as its MTA. As
is typical on such systems, the user's primary inbox is an mbox file called
Mailbox, in their home directory. Global shell config files /etc/csh.cshrc and
/etc/profile set the MAIL environment variable to ~/Mailbox for the users,
which is enough to satisfy their interactive mail clients such as pine, mutt,
and elm.

The mail-storages.txt file in the dovecot docs seems to say that dovecot will
not have a problem with this kind of setup. However, I can't figure out how to
make it work. The MAIL variable is only set for users who are using shells
like tcsh, bash, etc. The server apparently does not operate in a shell, so it
is looking in some other location, perhaps /var/mail/$USER, so everyone's
INBOX appears to be empty.

It would help if mail-storages.txt, when referring to environment variables
such as MAIL, would clarify *whose* environment variables are being referred
to. Is it the environment of the user who built dovecot? Is it the environment
of the user running the main dovecot process? Is it the environment of the
user who is checking their mail / the user that dovecot runs setuid as? When
and where do I set the MAIL variable so that dovecot will see it? Or is there
some other problem?

Any help appreciated...