[HEADS UP] PKGTOOLS_REQD bump and related changes

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

Hello all,
before the freeze I have commmitted the following large scale changes.
This can result in some fallout, so be warned:

(1) License infrastructure

The license check is now using pkg_admin and allows boolean expressions.
E.g. LICENSE= artistic OR gnu-gpl-v2.  If you get complains about
PKGSRC_ACCEPTABLE_LICENSES, check your mk.conf.  Valid license names are
lower case only.

(2) @dirrm

pkg_delete is performing automatic pruning of directories now. Empty
directories in packages can be requested by @pkgdir in the PLIST and
will be considered. As some packages had quite a bit of magic related
to @dirrm entries, there might be some fallout. I am running a bulk
build now to identify those issues.

(3) PKGTOOLS_REQD bump and bulk builds

For NetBSD 4 and later, make sure to update to the head of the release
branch to get the correct pkg_install.  For NetBSD 3 and older as well
as !NetBSD systems, make sure your bootstrap is new enough.

Joerg