anchor.diff: -{ stdenv, fetchFromGitHub
  -, pkgconfig, bison, flex
  -, tcl, readline, libffi, python3
  -, protobuf, zlib
  +{ stdenv
  +, bison
  +, fetchFromGitHub
  +, flex
  +, libffi
  +, pkgconfig
  +, protobuf
  +, python3
  +, readline
  +, tcl
   , verilog
  +, zlib
   }:
   
   with builtins;
  
positive.code:   nativeBuildInputs = [ pkgconfig ];
    buildInputs = [ tcl readline libffi python3 bison flex protobuf zlib ];
  
    makeFlags = [ "ENABLE_PROTOBUF=1" ];
  
    patchPhase = ''
      substituteInPlace ../yosys-abc/Makefile \
  
negative.code:     ln -s ../yosys-abc abc
      make config-${if stdenv.cc.isClang or false then "clang" else "gcc"}
      echo 'ABCREV := default' >> Makefile.conf
  
      # we have to do this ourselves for some reason...
      (cd misc && ${protobuf}/bin/protoc --cpp_out ../backends/protobuf/ ./yosys.proto)
  