ghostscript-afpl vs ghostscript-gnu

[Mark Linimon]

> Eww, how did this superfluous variable get into bsd.port.mk?  You're
> supposed to use GHOSTSCRIPT_PORT to specify which of the n ghostscript
> ports you want to use.

As ports/36112, which was originally someone else's PR, but one
on which you had commented "this patch needs to be reworked for
the current bsd.port.mk" which I then did.  See audit log for
details.  You've got my permission to change it if you hate it.

mcl