anchor.diff:    passthru = {
       srcVerification = fetchurl rec {
         failEarly = true;
  -      urls = tarballUrls "1.7.1";
  +      urls = tarballUrls "1.7.2";
         pgpsigUrls = map (n: "${n}.sig") urls;
         pgpKeyFingerprint = "D869 2123 C406 5DEA 5E0F  3AB5 249B 39D2 4F25 E3B6";
  -      outputHash = "450d9cfcbf1611c64dbe3bd04b627b83379ef89f11406d94c8bba305e36d7a95";
  +      outputHash = "3d35df906d6eab354504c05d749a9b021944cb29ff5f65c8ef9c3dd5f7b6689f";
         inherit (src) outputHashAlgo;
       };
     };
  
positive.code:     "mirror://gnupg/libgcrypt/libgcrypt-${version}.tar.bz2"
    ];
  
    version = "1.7.1";
  in
  stdenv.mkDerivation rec {
    name = "libgcrypt-${version}";
  
negative.code:   src = fetchurl {
      url = tarballUrls version;
      allowHashOutput = false;
      sha256 = "3d35df906d6eab354504c05d749a9b021944cb29ff5f65c8ef9c3dd5f7b6689f";
    };
  
    buildInputs = [
  