anchor.diff:          source = pkgs.runCommand "empty" {} "ensureDir $out";
           target = "/nix/store";
         }
  -      { # Another quick hack: the kernel needs a systemConfig
  -        # parameter in menu.lst, but the system config depends on
  -        # menu.lst.  Break the cyclic dependency by having a /system
  -        # symlink on the CD, and having menu.lst refer to /system.
  -        source = pkgs.runCommand "system" {}
  -          "ln -s ${config.system.build.toplevel} $out";
  -        target = "/system";
  -      }
  -      { # Idem for the stage-2 init script.
  -        source = pkgs.runCommand "system" {}
  -          "ln -s ${config.system.build.bootStage2} $out";
  -        target = "/init";
  -      }
       ];
   
     # The Grub menu.
  
positive.code: 
    # We need squashfs in the initrd to mount the compressed Nix store,
    # and aufs to make the root filesystem appear writable.
    boot.extraModulePackages = (pkgs.lib.optional 
      (! config.boot.kernelPackages.kernel.features ? aufs) 
      config.boot.kernelPackages.aufs);
    boot.initrd.extraKernelModules = ["aufs" "squashfs"];
  
negative.code:       '';
      };
  
      isoImage.contents = mkOption {
        example =
          [ { source = pkgs.memtest86 + "/memtest.bin";
              target = "boot/memtest.bin";
  