anchor.diff:    # The installer.
     nixosInstaller = import ./installer.nix {
       inherit (pkgs) stdenv genericSubstituter;
  -    nix = pkgs.nixUnstable; # needs the exportReferencesGraph feature
  +    inherit nix;
  +    nix = pkgs.nixUnstable; 
       shell = pkgs.bash + "/bin/sh";
     };
   
  
positive.code:     system = pkgs.stdenv.system;
      allPackages = import ./pkgs/top-level/all-packages.nix;
    };
  
  
    # Determine the set of modules that we need to mount the root FS.
  
negative.code:       pkgs.sysklogd
        pkgs.sysvinit
  #      pkgs.vim
        nix
        nixosInstaller
      ];
  
  