anchor.diff:    src = fetchurl {
       urls = tarballUrls version;
       hashOutput = false;
  -    sha256 = "b52fd3bc9693de16db93aa23a11a56f3cdb3fbf005a360145401ab5d252490f5";
  +    sha256 = "644b6b03b285fb0ace02d241d59483d98bc462729d8bb3608d5cad5532f3d2f0";
     };
  -
  -  nativeBuildInputs = [
  -    lzip
  -  ];
   
     configureFlags = [
       "--disable-doc"
  
positive.code: { stdenv
  , fetchurl
  , lzip
  }:
  
  let
    version = "2.0.3";
  
    tarballUrls = version: [
      "mirror://gnu/libidn/libidn2-${version}.tar.lz"
    ];
  in
  stdenv.mkDerivation rec {
  
negative.code:   passthru = {
      srcVerification = fetchurl {
        failEarly = true;
        urls = tarballUrls "2.0.4";
        pgpsigUrls = map (n: "${n}.sig") src.urls;
        pgpKeyFingerprint = "1CB2 7DBC 9861 4B2D 5841  646D 0830 2DB6 A267 0428";
        inherit (src) outputHashAlgo;
        outputHash = "644b6b03b285fb0ace02d241d59483d98bc462729d8bb3608d5cad5532f3d2f0";
      };
    };
  
  