nixos/no-x-libs: add ghostscript

      ffmpeg_5 = super.ffmpeg_5.override { ffmpegVariant = "headless"; };

      # dep of graphviz, libXpm is optional for Xpm support

      gd = super.gd.override { withXorg = false; };

      ghostscript = super.ghostscript.override { cupsSupport = false; x11Support = false; };

      gobject-introspection = super.gobject-introspection.override { x11Support = false; };

      gpsd = super.gpsd.override { guiSupport = false; };

      graphviz = super.graphviz-nox;