anchor.diff:  let
   
   ###### interface
  +  inherit (pkgs.lib) mkOption types;
   
     options = {
   
  -    fileSystems = pkgs.lib.mkOption {
  +    fileSystems = mkOption {
         example = [
           { mountPoint = "/";
             device = "/dev/hda1";
  
positive.code:   inherit (pkgs) e2fsprogs;
    fileSystems = config.fileSystems;
    mountPoints = map (fs: fs.mountPoint) fileSystems;
    devices = map (fs: if fs ? device then fs.device else "LABEL=" + fs.label) fileSystems;
    fsTypes = map (fs: if fs ? fsType then fs.fsType else "auto") fileSystems;
    optionss = map (fs: if fs ? options then fs.options else "defaults") fileSystems;
    autocreates = map (fs: if fs ? autocreate then fs.autocreate else "0") fileSystems;
    mount = config.system.sbin.mount;
  
    job = ''
  
negative.code:         <literal>autocreate</literal> forces <literal>mountPoint</literal> to be created with 
          <command>mkdir -p</command> .
        ";
        type = types.nullOr (types.list types.optionSet);
  
        options =  {
  
          mountPoint = mkOption {
            example = "/mnt/usb";
            type = types.uniq types.string;
            description = "
              Location of the mounted the file system.
            ";
          };
  
          device = mkOption {
            default = null;
            example = "/dev/sda";
            type = types.uniq (types.nullOr types.string);
            description = "
              Location of the device.
            ";
          };
  
          label = mkOption {
            default = null;
            example = "root-partition";
            type = types.uniq (types.nullOr types.string);
            description = "
              Label of the device (if any).
            ";
          };
  
          fsType = mkOption {
            default = "auto";
            example = "ext3";
            type = types.uniq types.string;
            description = "
              Type of the file system.
            ";
          };
  
          options = mkOption {
            default = "defaults";
            example = "data=journal";
            type = types.string;
            merge = pkgs.lib.concatStringsSep ",";
            description = "
              Option used to mount the file system.
            ";
          };
  
          autocreate = mkOption {
            default = "0";
            type = types.uniq types.string;
            description = "
              Automatically create the mount point defined in
              <option>fileSystems.*.mountPoint</option>.
            ";
          };
  
          # Should be moved inside boot-stage-1.nix
          neededForBoot = mkOption {
            default = false;
            type = types.enable;
            description = "
              Mount this file system to boot on NixOS.
            ";
          };
  
        };
      };
    
      system.sbin.mount = mkOption {
        internal = true;
        default = pkgs.utillinuxng.override {
          buildMountOnly = true;
  