anchor.diff:  
     gdb = callPackage ../development/tools/misc/gdb {
       hurd = gnu.hurdCross;
  -    readline = readline63;
       inherit (gnu) mig;
     };
   
  
positive.code:     suitesparse = null;
      openjdk = null;
      gnuplot = null;
      readline = readline63;
    };
    octaveFull = (lowPrio (callPackage ../development/interpreters/octave {
      fltk = fltk13;
  
negative.code: 
    raul = callPackage ../development/libraries/audio/raul { };
  
    readline = readline6;
    readline6 = readline63;
  
    readline4 = callPackage ../development/libraries/readline/readline4.nix { };
  
    readline5 = callPackage ../development/libraries/readline/readline5.nix { };
  
    readline62 = callPackage ../development/libraries/readline/readline6.nix { };
  
    readline63 = callPackage ../development/libraries/readline/readline6.3.nix { };
  
  