empty directories after pkg_delete -r \*

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Some directories regularly stay for me after a "pkg_delete -r \*"
though they are empty and shouldn't be there:

lib/lua/5.1
share/htdig/common

lib/lua/5.1 is handled using @pkgdir in lang/lua and in
graphics/graphviz. Perhaps reference counting doesn't manage two
@pkgdir entries for the same directory well. Since I didn't see a
reason for the entry in graphics/graphviz, I removed it there.

share/htdig/common isn't mentioned explicitly as @pkgdir; some files
are installed there by www/htdig, and some databases are created there
which get deleted using @unexec ${RM}. Is the clean-empty-dirs step
too late (or too dumb) to notice this?

Cheers,
 Thomas