Remove `-p' from mkdir arguments, it is already part of ${MKDIR}.
While here substitute a couple of ${PREFIX} by `%D' in
`@exec ${MKDIR} ...' lines and add a couple of missing `%D' in such lines too!
${LOCALBASE}/etc, and is the parent directory of the priv package's
user configuration data.
Modify Makefile to pick up this definition, and pass it on as an argument
to the configure script.
Modify the PLIST to include this location, and pre-process the PLIST at
install time to set the correct location.