This is a diff under test for fixing the case when TESTSBASE != /usr/tests, as noticed when I tried to change this to a custom prefix at EMC / Isilon.
make buildworld/make installworld was run and was successful when executed from a chroot; unfortunately running kyua test doesn't work all that well when executed from an absolute path if DESTDIR != / (but that's a separate commit that needs to be done, potentially).