ghostscript5 package as (a) we should be encouraging people to use the
packages collection where possible, and (b) it messes up the package
depencies if we don't, to the extent that pkg_delete will have problems.
We need some dependency here, and it's either on ${LOCALBASE}/bin/gs
to pick up the ghostscript 5 package's gs binary, or simply gs, to
pick up any gs binary in the path. The latter was chosen for the
moment.
