Is there a good way to use pkg_comp to rebuild just the out-of-date
packages?

I know how to use pkg_comp to rebuild everything: use pkg_chk -g
to produce a list, and put that into the pkg_comp file.  I can also 
delete/rebuild just the out-of-date stuff by using lintpkgsrc -i
and pkgdepgraph -D/-R.  I'd like to do the latter in a chroot'd 
partition without having to recompile -- or even pkg_tarup plus install 
under chroot -- all of the dependencies that aren't out of date.  Is 
there any good way to do that?  (If I had to, I'd settle for something 
that automatically built tarballs of the dependencies, for automatic 
preinstallation in the pkg_comp area, but I don't even know a good way 
to do that.)



		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb