anchor.diff:  
     src = fetchurl {
       url = "${baseUrl}/${name}.tar.gz";
  -    sha256Url = "${baseUrl}/SHA256SUMS";
  -    sha256 = "0d4a77ff26bcee79fa8afe0125e0df6ae9e798b6b36782fa29e28febf7cfce24";
  +    hashOutput = false;
  +    sha256 = "e90561256a3271486162c1fbe8d614d118c333d36a4455be2af8688bd420a65d";
     };
   
     buildInputs = [
  
positive.code: 
    passthru = {
      inherit version;
    };
  
    meta = with stdenv.lib; {
  
negative.code: }:
  
  let
    version = "3.31";
  
    baseUrl = "https://ftp.mozilla.org/pub/mozilla.org/security/nss/releases"
      + "/NSS_${stdenv.lib.replaceStrings ["."] ["_"] version}_RTM/src";
  