subset machinery for bulk pkgsrc builds

["Cary G. Gray" <Cary.G.Gray%wheaton.edu@localhost>]

I'm still a bit confused about how to manage some of the bulk build 
machinery to build only a subset of pkgsrc.  In particular, I'm unsure 
about which variables to set--and where/how they should be set.  I've
read and reread several chapters of "The pkgsrc guide", and I've done a 
modest amount of reading scripts.  For context, I've been invoking the
mk/bulk/build script from within a chroot created with pkg_comp (_not_ 
using the pkg_comp lists of packages to build).  I've been using the 
stable pkgsrc branches (currently 2006Q2) on netbsd-3-0, architecture 
i386.

The pkgsrc guide mentions setting SPECIFIC_PKGS=1 in /etc/mk.conf, in 
which case the list of package directories is taken from several 
additional variables {SITE,HOST,GROUP,USER}_SPECIFIC_PKGS.  But I can't 
tell from the guide whether those variables have to be set in /etc/mk.conf 
or in mk/bulk/build.conf.  I've just wandered back into 
mk/defaults/mk.conf, which leads to me believe the former.

In mk/bulk/build.conf-example, there is a comment that says to set PKGLIST 
to a list of directories in order to build a subset of packages.  That's 
the mechanism I've been using, but I've observed that it does not do a 
very good job with dependencies.  Is that mechanism deprecated?  Should a 
comment be added there to that effect?

Specific questions:

1. Am I right to infer that setting PKGLIST is (should be) deprecated in 
favor of the SPECIFIC_PKGS mechanism?

2. Is it possible to set SPECIFIC_PKGS and the *_SPECIFIC_PKGS from 
mk/bulk/build.conf, or must those be in /etc/mk.conf?

Thanks,
        Cary Gray
        Cary.G.Gray%wheaton.edu@localhost