anchor.diff:      };
     };
   
  -  inherit (pkgs.lib) mkIf;
   in
   
   {
  
positive.code: {pkgs, config, ...}:
  
  ###### interface
  let
    inherit (pkgs.lib) mkOption;
  
    options = {
  
  
negative.code:     '';
  
    environment.systemPackages =
      optional config.fonts.enableFontDir config.system.build.x11Fonts ++
      optional config.fonts.enableFontConfig pkgs.fontconfig;
  }
  