anchor.diff:    passthru = {
       srcVerification = fetchurl rec {
         failEarly = true;
  -      urls = tarballUrls "8.41";
  +      urls = tarballUrls "8.42";
         pgpsigUrls = map (n: "${n}.sig") urls;
         pgpKeyFingerprint = "45F6 8D54 BBE2 3FB3 039B  46E5 9766 E084 FB0F 43D8";
         inherit (src) outputHash outputHashAlgo;
  
positive.code:   src = fetchurl {
      url = tarballUrls version;
      hashOutput = false;
      sha256 = "e62c7eac5ae7c0e7286db61ff82912e1c0b7a0c13706616e94a7dd729321b530";
    };
  
    buildInputs = optionals pcregrep [
  
negative.code:     "mirror://sourceforge/pcre/pcre/${version}/pcre-${version}.tar.bz2"
    ];
  
    version = "8.42";
  in
  stdenv.mkDerivation rec {
    name = "pcre-${version}";
  