Log Message:
ghostscript-gpl: Clarify support status

Adjust language as we approach 11 years since the last upstream
release; it's now "very old" rather than "old" and it is also
unmaintained.  Note that the last security patch happened in 2017.

Drop sentence that the cups option provides cups support and is off by
default.  That's not unusual and that's what "make show-options" is
for.