anchor.diff:        src = fetchgit {
           url = "http://git.code.sf.net/p/net-tools/code";
           rev = gitRev;
  -        sha256 = "1h8iryf5qc4svyz2ri1v4a8117w4r79rw6iqn8n7qavg0w45b30k";
  +        sha256 = "1f7myyc490nq29dhs45sm2njxwdnck69pm9ixiwgj44mxdmj3rbm";
         };
   
         buildPhase = ''
  -        cp -rv ${src} ${name}
  -        tar Jcfv ${name}.tar.xz ${name}
  +        cd ..
  +        tar Jcfv ${name}.tar.xz $sourceRoot
         '';
   
         installPhase = ''
  
positive.code: }:
  
  let
    date = "2016-02-15";
    gitRev = "bd8bceaed2311651710331a7f8990c3e31be9840";
  in
  
  stdenv.mkDerivation rec {
  
negative.code: 
    src = fetchurl {
      name = "${name}.tar.xz";
      multihash = "QmSDSsjomFu6VZ5szCWGh9hyYQDFRKzFbQRJ1Deafh1cm7";
      sha256 = "fc8ebe223a7144b6cde07eceac3b7ed7e71b350107002a21162542680ddfee2d";
    };
  
    nativeBuildInputs = [
  