anchor.diff: -{ stdenv
  +{ stdenv, lib
   , abc-verifier
   , bash
   , bison
  
positive.code: 
    setupHook = ./setup-hook.sh;
  
    meta = with stdenv.lib; {
      description = "Open RTL synthesis framework and tools";
      homepage    = "http://www.clifford.at/yosys/";
      license     = licenses.isc;
  
negative.code:   };
  
    enableParallelBuilding = true;
    nativeBuildInputs = [ pkg-config bison flex ];
    buildInputs = [ tcl readline libffi python3 protobuf zlib ];
  
    makeFlags = [ "ENABLE_PROTOBUF=1" "PREFIX=${placeholder "out"}"];
  
    patches = [
      ./plugin-search-dirs.patch
    ];
  
    postPatch = ''
      substituteInPlace ./Makefile \
        --replace 'echo UNKNOWN' 'echo ${builtins.substring 0 10 src.rev}'
  
  