anchor.diff:      atool
       autojump
       bazaar
  -    borgbackup
       curl
       cvs
       editorconfig-core-c
  -    gimp
       git
       git-lfs
       gitAndTools.hub
       gnupg
       gphoto2
  +    graphviz
       haskellPackages.pandoc
       haskellPackages.sizes
       htop
  
positive.code:   fetchNixpkgs = import ./fetchNixpkgs.nix;
  
    nixpkgs = fetchNixpkgs {
       rev = "6db7f92cc2af827e8b8b181bf5ed828a1d0f141d";
       sha256 = "1wpnln6spcvqvrfqw49z83ky5v8gw951f818q5123l0qpywpmfsq";
    };
  
    pkgs = import nixpkgs { config = {}; };
  
negative.code:     w3m
      wget
      ] ++ (if stdenv.isDarwin then [] else [
          borgbackup
          calibre
          crawl
          darcs
  