since I heard no feedback here from my patch, I've submitted my patch as
pkg/15827.  it fixes the following problems:

* failed su for pkg_delete during make update does not remove DDIR on
  failure, resulting in assumption that pkg_delete incorrectly succeeded
  when make update is run again, which leads to failure of make install
  and requirement of manual intervention.

* pkg_delete gets run unconditionally during make update, resulting in
  pkg_deletes of uninstalled packages.

could someone with the authority could either commit this, clean it up
and commit it, or critique it so I can clean it up?  thanks.

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | agrier@poofygoof.com