anchor.diff: -{ stdenv, fetchFromGitHub, ocaml, opam }:
  +{ stdenv, fetchFromGitHub, ocamlPackages, opaline }:
   
   stdenv.mkDerivation rec {
     name = "jbuilder-${version}";
  
positive.code:     description = "Fast, portable and opinionated build system";
      maintainers = [ stdenv.lib.maintainers.vbgl ];
      license = stdenv.lib.licenses.asl20;
      inherit (ocaml.meta) platforms;
    };
  }
  
negative.code:     sha256 = "0571lzm8caq6wnia7imgy4a27x5l2bvxiflg0jrwwml0ylnii65f";
    };
  
    buildInputs = with ocamlPackages; [ ocaml findlib ];
  
    dontAddPrefix = true;
  
    installPhase = "${opaline}/bin/opaline -prefix $out -libdir $OCAMLFIND_DESTDIR";
  
    preFixup = "rm -rf $out/jbuilder";
  
  