anchor.diff:    src = fetchurl {
       urls = tarballUrls version;
       hashOutput = false;
  -    sha256 = "95416080329298a13269e13175041b530cec3d98b54cafae9424b8dfd22078b1";
  +    sha256 = "fc734732b506d878753ec6606982bf7b936e868c25c30ddb0d83f7d7056381fe";
     };
   
     configureFlags = [
  
positive.code: }:
  
  let
    version = "2.1.1";
  
    tarballUrls = version: [
      "mirror://gnu/libidn/libidn2-${version}.tar.gz"
  
negative.code:   passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "2.2.0";
        inherit (src) outputHashAlgo;
        outputHash = "fc734732b506d878753ec6606982bf7b936e868c25c30ddb0d83f7d7056381fe";
        fullOpts = {
          pgpsigUrls = map (n: "${n}.sig") urls;
          pgpKeyFingerprint = "1CB2 7DBC 9861 4B2D 5841  646D 0830 2DB6 A267 0428";
  