anchor.diff:  { stdenv, fetchFromGitHub
   , pkgconfig, bison, flex
   , tcl, readline, libffi, python3
  -, protobuf
  +, protobuf, zlib
   }:
   
   with builtins;
   
   stdenv.mkDerivation rec {
  -  name = "yosys-${version}";
  -  version = "2019.04.23";
  +  pname = "yosys";
  +  version = "2019.08.13";
   
     srcs = [
       (fetchFromGitHub {
         owner  = "yosyshq";
         repo   = "yosys";
  -      rev    = "d9daf09cf3aab202b6da058c5e959f6375a4541e";
  -      sha256 = "0l27r9l3fvkqhmbqqpjz1f3ny4wdh5mdc7jlnbgy6nxx6vqcmkh0";
  +      rev    = "19d6b8846f55b4c7be705619f753bec86deadac8";
  +      sha256 = "185sbkxajx3k9j03n0cxq2qvzwfwdbcxp19h8vnk7ghd5y9gp602";
         name   = "yosys";
       })
   
  
positive.code:     (fetchFromGitHub {
        owner  = "berkeley-abc";
        repo   = "abc";
        rev    = "3709744c60696c5e3f4cc123939921ce8107fe04";
        sha256 = "18a9cjng3qfalq8m9az5ck1y5h4l2pf9ycrvkzs9hn82b1j7vrax";
        name   = "yosys-abc";
      })
    ];
  
negative.code: 
    enableParallelBuilding = true;
    nativeBuildInputs = [ pkgconfig ];
    buildInputs = [ tcl readline libffi python3 bison flex protobuf zlib ];
  
    makeFlags = [ "ENABLE_PROTOBUF=1" ];
  
  