anchor.diff:  
   let
     inherit (stdenv.lib)
  -    enFlag
  -    optionals
  -    wtFlag;
  +    boolEn
  +    boolWt
  +    optionals;
   
     source = (import ./sources.nix { })."${channel}";
   in
  
positive.code: 
    src = fetchurl {
      url = "mirror://gnome/sources/clutter/${channel}/${name}.tar.xz";
      sha256Url = "mirror://gnome/sources/clutter/${channel}/${name}.sha256sum";
      inherit (source) sha256;
    };
  
  
negative.code:     "--disable-installed-tests"
      "--disable-always-build-tests"
      "--disable-examples"
      "--${boolWt (xorg != null)}-x"
    ];
  
    passthru = {
      srcVerification = fetchurl {
        inherit (src)
          outputHash
          outputHashAlgo
          urls;
        sha256Url = "https://download.gnome.org/sources/clutter/"
          + "${channel}/${name}.sha256sum";
        failEarly = true;
      };
    };
  
    meta = with stdenv.lib; {
      description = "Library for creating graphical user interfaces";
  