anchor.diff:  
     passthru = {
       srcVerification = fetchurl rec {
  -      inherit (src) outputHashAlgo;
  -      urls = tarballUrls "1.15.1";
  +      failEarly = true;
  +      urls = tarballUrls "1.16";
         pgpsigUrls = map (n: "${n}.sig") urls;
         pgpKeyFingerprints = [
           # Mathieu Lirzin
           "F2A3 8D7E EB2B 6640 5761  070D 0ADE E100 9460 4D37"
         ];
  -      outputHash = "af6ba39142220687c500f79b4aa2f181d9b24e4f8d8ec497cea4ba26c64bedaf";
  -      failEarly = true;
  +      outputHash = "f98f2d97b11851cbe7c2d4b4eaef498ae9d17a3c2ef1401609b7b4ca66655b8a";
  +      inherit (src) outputHashAlgo;
       };
     };
   
  
positive.code: }:
  
  let
    version = "1.15.1";
  
    tarballUrls = version: [
      "mirror://gnu/automake/automake-${version}.tar.xz"
  
negative.code: 
    src = fetchurl {
      url = tarballUrls version;
      hashOutput = false;
      sha256 = "f98f2d97b11851cbe7c2d4b4eaef498ae9d17a3c2ef1401609b7b4ca66655b8a";
    };
  
    nativeBuildInputs = [
  