Log message:
Remove mk/find-prefix.mk usage from the mail category.

The find-prefix infrastructure was required in a pkgviews world where
packages installed from pkgsrc could have different installation
prefixes, and this was a way for a dependency prefix to be determined.

Now that pkgviews has been removed there is no longer any need for the
overhead of this infrastructure.  Instead we use BUILDLINK_PREFIX.pkg
for dependencies pulled in via buildlink, or LOCALBASE/PREFIX where the
dependency is coming from pkgsrc.

Provides a reasonable performance win due to the reduction of `pkg_info
-qp` calls, some of which were redundant anyway as they were duplicating
the same information provided by BUILDLINK_PREFIX.pkg.

Log message:
Placate pkglint by abolishing LOCALBASE (no functional change
intended) and adding LICENSE and NO_CHECKSUM. Bump version.

Log message:
Remove pkgviews: don't set PKG_INSTALLATION_TYPES in Makefiles.

Log message:
Bump default limits for qmail-{pop3d,smtpd} to 140MB, since a process
on NetBSD/amd64 needs 128MB for a stack these days (thanks riastradh@).
Bump version.

Log message:
Remove example rc.d scripts from PLISTs.

These are now handled dynamically if INIT_SYSTEM is set to "rc.d", or
ignored otherwise.

Log message:
Drop PKG_DESTDIR_SUPPORT setting, "user-destdir" is default these days.

Log message:
Remove @dirrm entries from PLISTs

Log message:
Remove redundant NO_CHECKSUM and EXTRACT_ONLY definitions.

Log message:
Mechanical changes to add DESTDIR support to packages that install
their files via a custom do-install target.

Log message:
Quell pkglint: add QMAIL_QUEUE_EXTRA to BUILD_DEFS.