cups: circular dependency with 'gs' option set

["Steven M. Bellovin" <smb%cs.columbia.edu@localhost>]

When trying to build cups on a system with no other packages installed,
with the 'gs' option set, I got this:

        => Returning to build of ghostscript-8.64nb3
        => Full dependency perl>=5.0: found perl-5.10.0nb6
        => Full dependency libX11>=1.1: found libX11-1.2.1
        => Full dependency libXt>=1.0.0: found libXt-1.0.5nb1
        => Full dependency libXext>=0.99.0: found libXext-1.0.5nb1
        => Full dependency cups>=1.2.12nb3: NOT found
        => Verifying package clean for ../../print/cups
        ERROR: This package has set PKG_FAIL_REASON:
        ERROR: Circular dependency detected
        *** Error code 1

        Stop.
        make: stopped in /usr/pkgsrc/print/cups
        *** Error code 1

        Stop.
        make: stopped in /usr/pkgsrc/print/ghostscript
        *** Error code 1

        Stop.
        make: stopped in /usr/pkgsrc/print/cups


I confess I'm surprised that ghostscript depends on cups at all.  (I have
cups set as a global option.)

                --Steve Bellovin, http://www.cs.columbia.edu/~smb