anchor.diff:  
     wtforms = callPackage ../development/python-modules/wtforms { };
   
  -  graph-tool = callPackage ../development/python-modules/graph-tool/2.x.x.nix { };
  +  graph-tool = callPackage ../development/python-modules/graph-tool/2.x.x.nix {
  +    inherit (pkgs) pkgconfig;
  +  };
   
     grappelli_safe = callPackage ../development/python-modules/grappelli_safe { };
   
  
positive.code: 
    kmsxx = (callPackage ../development/libraries/kmsxx {
      inherit (pkgs.kmsxx) stdenv;
    }).overrideAttrs (oldAttrs: {
      name = "${python.libPrefix}-${pkgs.kmsxx.name}";
    });
  
negative.code:     inherit (pkgs) pkgconfig;
    };
  
    pycangjie = disabledIf (!isPy3k) (callPackage ../development/python-modules/pycangjie {
      inherit (pkgs) pkgconfig;
    });
  
    pycrc = callPackage ../development/python-modules/pycrc { };
  
  