anchor.diff:  { stdenv
  -, cmake
   , fetchgit
  -, go
  -, ninja
  -, perl
  +, which
   
   , openssl
   , protobuf-cpp
  
positive.code: }:
  
  let
    version = "2016-10-17";
  in
  stdenv.mkDerivation {
    name = "grpc-${version}";
  
negative.code:   src = fetchgit {
      version = 2;
      url = "https://github.com/grpc/grpc.git";
      rev = "566608e275c8b4b7bb9f8f61bb4d477e9c2dabc0";
      sha256 = "0wx42jwys7bss13b2qj48dw9x9r79zz39iynn1f3y64yyj872bza";
    };
  
    nativeBuildInputs = [
      which
    ];
  
    buildInputs = [
  