anchor.diff:        tree
         apg
         postgresql
  +      qtcreator
       ];
     };
   
  
positive.code:           ++ x11-tools
            ++ music-apps
            ++ go-env
            ++ node-env;
        };
  
        python2-tools = pkgs.buildEnv {
          name = "python2-tools";
          paths = with python27Packages; pkg-set {
            all = [
              ipython
              flake8
              virtualenv
              Fabric
            ];
            linux = [ pylint ];
          };
        };
  
        python3-tools = pkgs.buildEnv {
          name = "python3-tools";
          paths = with python35Packages; pkg-set {
            all = [
              ipython
              flake8
              virtualenv
              Fabric
            ];
            linux = [ pylint ];
          };
        };
      };
    }
  
negative.code:     glide
    ];
  
    python2-env = with python27Packages; pkg-set {
      all = [
        python27Full
        ipython
        flake8
        virtualenv
        Fabric
      ];
      linux = [ pylint ];
    };
  
  in
    rec {
      allowUnfree = true;
  
      firefox = {
        enableAdobeFlash = true;
        enableAdobeFlashDRM = true;
      };
  
      packageOverrides = pkgs : rec {
        dev-env = pkgs.buildEnv {
  