Log message:
mail: Replace RMD160 checksums with BLAKE2s checksums

All checksums have been double-checked against existing RMD160 and
SHA512 hashes

The following distfiles were unfetchable (possibly fetched
conditionally?):

./mail/qmail/distinfo netqmail-1.05-TAI-leapsecs.patch

Log message:
mail: Remove SHA1 hashes for distfiles

Log message:
Remove DJB_RESTRICTED, no longer used.

Log message:
Retire 'djbware-errno-hack' and associated options.mk cleverness.
Instead:

1. Package makefiles including their own options.mk
2. Packages say "SUBST_CLASSES+=djberrno" to get the hack, if needed
3. Packages adjust SUBST_FILES.djberrno, if needed

Should fix bulk build failures due to multiple inclusions of options.mk
and/or incorrect definitions of DJB_ERRNO_HACK.

Approved during the freeze by wiz@.

Log message:
mail/qconfirm: does not have error.h

Log message:
Initial import of qconfirm, an implementation of a delivery confirmation
process for a mailing list or mail address. It is invoked by qmail-local
through a dot-qmail file, and can reduce the amount of junk mail hitting
a mailbox or the mailboxes of mailing list subscribers. qconfirm
performs this delivery confirmation process either sender based or
message based.

When used for a public mail address, not a mailing list, qconfirm is
capable of detecting follow-ups on mail messages originated from this
mail address, and doesn't request delivery confirmation is this case.
qconfirm also is able to identify delivery confirmation requests from
recipients of mail messages, and automatically confirms the delivery
if desired.