Log message:
Split plotutils and gnuplot into '<pkgname>' and '<pkgname>-nox11' each
(alternatively, we could have renamed one to '<pkgname>-x11', but for the
element of least surprise, the default remains x11 enabled).
This will work much better than the previous attempt to build two packages
from one Makefile, which wasn't all thought out wrt to dependencies, buildlinks etc.
Bump PKGREVISION on plotutils and gnuplot for this.