anchor.diff:  }:
   
   stdenv.mkDerivation rec {
  -  name = "groff-1.22.3";
  +  name = "groff-${version}";
  +  version = "1.22.3";
   
     src = fetchurl {
       url = "mirror://gnu/groff/${name}.tar.gz";
       sha256 = "1998v2kcs288d3y7kfxpvl369nqi06zbbvjzafyvyl3pr7bajj1s";
     };
   
  -  outputs = [ "out" "man" "doc" "info" ];
  +  outputs = [ "out" "man" "doc" "info" "perl" ];
   
     enableParallelBuilding = false;
   
  
positive.code:       --replace "@PNMTOPS_NOSETPAGE@" "${netpbm}/bin/pnmtops -nosetpage"
    '';
  
    buildInputs = [ ghostscript psutils netpbm ];
    nativeBuildInputs = [ perl ];
  
    # Builds running without a chroot environment may detect the presence
    # of /usr/X11 in the host system, leading to an impure build of the
  
negative.code:       version gxditview of the X11 xditview previewer, and an
        implementation of the -mm macros.
      '';
  
      outputsToInstall = [ "out" "perl" ];
    };
  }
  