Use the default LIBOWN, etc. instead of clobbering the defaults to bin,
etc., so that (this part of) `LIBOWN=... make world' can be run by users
other than root. Actually, use BINOWN instead of LIBOWN, since the files
that we install in /usr/libdata are not libraries, and LIBOWN is not
used for anything else in /usr/libdata.

Rewrote all the rules and cleaned up.