mailspool probing

[David Holland <dholland-pkgtech%netbsd.org@localhost>]

A number of packages attempt to probe the mail spool location and type
when you build them; some of them fail gratuitously if your build
chroot is missing /var/mail.

I have been thinking that pkgsrc should provide infrastructure for
this, so that packages with rickety probe logic can be made robust and
also so that people who want non-default behavior can configure it in
one place.

This came up again today so I was thinking about specific mechanisms,
and I keep going back and forth between whether it should be done with
package options or by separate config vars. On the one hand, options
are tidier and this is exactly the sort of thing for which options are
intended; on the other hand, the default settings are platform-
dependent (and not per-package) and there doesn't seem to be any
precedent for setting default options in mk/platform/*.mk.

Thoughts?

I guess there are two settings: (1) the location of mailboxes
(/var/mail, /var/spool/mail, homedir) and (2) the type of the
mailboxes and mail spool (bsd mboxes, sysv mboxes, maildir, etc.)

Do any of the, ahem, vintage platforms pkgsrc supports still use a
System V-style mail spool? (where the mail spool is mode 775, group
mail, and programs accessing mail need to be setgid mail)

One of the things this infrastructure can help with is to avoid
installing mailers setgid mail when they don't need to be; there are
at least a couple mail packages that are getting this wrong right now.

-- 
David A. Holland
dholland%netbsd.org@localhost