anchor.diff:    src = fetchurl {
       url = tarballUrls version;
       hashOutput = false;
  -    sha256 = "f98f2d97b11851cbe7c2d4b4eaef498ae9d17a3c2ef1401609b7b4ca66655b8a";
  +    sha256 = "5d05bb38a23fd3312b10aea93840feec685bdf4a41146e78882848165d3ae921";
     };
   
     nativeBuildInputs = [
  
positive.code: }:
  
  let
    version = "1.16";
  
    tarballUrls = version: [
      "mirror://gnu/automake/automake-${version}.tar.xz"
  
negative.code:   passthru = {
      srcVerification = fetchurl rec {
        failEarly = true;
        urls = tarballUrls "1.16.1";
        pgpsigUrls = map (n: "${n}.sig") urls;
        pgpKeyFingerprints = [
          # Mathieu Lirzin
          "F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37"
        ];
        outputHash = "5d05bb38a23fd3312b10aea93840feec685bdf4a41146e78882848165d3ae921";
        inherit (src) outputHashAlgo;
      };
    };
  