anchor.diff:        '';
       };
   
  -    isoImage.contents = pkgs.lib.mkOption {
  +    isoImage.contents = mkOption {
         example =
           [ { source = pkgs.memtest86 + "/memtest.bin";
               target = "boot/memtest.bin";
  
positive.code: # configuration.  The derivation for the ISO image will be placed in
  # config.system.build.isoImage.
  
  {config, pkgs, ...}:
  
  let
  
    options = {
  
      isoImage.isoName = pkgs.lib.mkOption {
        default = "cd.iso";
        description = ''
          Name of the generated ISO image file.
        '';
      };
  
      isoImage.compressImage = pkgs.lib.mkOption {
        default = false;
        description = ''
          Whether the ISO image should be compressed using
  
negative.code: 
    # We need squashfs in the initrd to mount the compressed Nix store,
    # and aufs to make the root filesystem appear writable.
    boot.extraModulePackages = (optional 
      (! config.boot.kernelPackages.kernel.features ? aufs) 
      config.boot.kernelPackages.aufs);
    boot.initrd.extraKernelModules = ["aufs" "squashfs"];
  