pkg - Shared object "libarchive.so.5" not found, required by "pkg"

I just upgraded a machine from 9.1-RC3 to 10-CURRENT.
pkg was installed on 9.1, but after an upgrade to 10-CURRENT pkg no
longer runs due to missing shared library.
10-CURRENT was built (and installed) twice. I guess the library was
installed when I was at 9.1-RC3 but was deleted during make
delete-old.

Rebuilding pkg from src/usr.sbin/pkg did not do the trick. For some
reason it was still linking to the old library.
Any hints?

-- 
chs,