anchor.diff:  }:
   
   let
  -  version = "5.18.12";
  +  version = "5.18.14";
   
     tarballUrls = version: [
       "mirror://gnu/autogen/rel${version}/autogen-${version}.tar.xz"
  
positive.code:       -e 's,guile_versions_to_search=",\02.2 ,g' \
        -i configure
  
      sed -i 's,< 201000,< 203000,g' agen5/guile-iface.h
    '';
  
    passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "5.18.12";
        pgpsigUrls = map (n: "${n}.sig") urls;
        pgpKeyFingerprint = "44A0 88E2 95C3 A722 C450  590E C9EF 76DE B74E E762";
        inherit (src) outputHashAlgo;
        outputHash = "be3ba62e883185b6ee8475edae97d7197d701d6b9ad9c3d2df53697110c1bfd8";
      };
    };
  
  
negative.code:   src = fetchurl {
      urls = tarballUrls version;
      hashOutput = false;
      sha256 = "ffc7ab99382116852fd4c73040c124799707b2d9b00a60b54e8b457daa7a06e4";
    };
  
    nativeBuildInputs = [
  