anchor.diff:      version = "8.06.10";
       sha256 = "06cck7wijq4zdshzhxm6jyl8k3j0zglj2axsyfk6q1sq754zyf4a";
     };
  -}.${builtins.substring 0 4 ocaml.version};
  + };
  + param = params . ${lib.versions.majorMinor ocaml.version}
  +   or (throw "labltk is not available for OCaml ${ocaml.version}");
   in
   
   stdenv.mkDerivation rec {
     inherit (param) version src;
     name = "ocaml${ocaml.version}-labltk-${version}";
   
  -  buildInputs = [ ocaml findlib tcl tk ];
  +  buildInputs = [ ocaml findlib tcl tk makeWrapper ];
   
     configureFlags = [ "--use-findlib" "--installbindir" "$(out)/bin" ];
     dontAddPrefix = true;
  
positive.code:   postInstall = ''
      mkdir -p $OCAMLFIND_DESTDIR/stublibs
      mv $OCAMLFIND_DESTDIR/labltk/dlllabltk.so $OCAMLFIND_DESTDIR/stublibs/
    '';
  
    meta = {
  
negative.code: { stdenv, lib, makeWrapper, fetchzip, ocaml, findlib, tcl, tk }:
  
  let
   params =
    let mkNewParam = { version, sha256, rev ? version }: {
      inherit version;
      src = fetchzip {
        url = "https://github.com/garrigue/labltk/archive/${rev}.tar.gz";
        inherit sha256;
      };
    }; in
   rec {
    "4.06" = mkNewParam {
      version = "8.06.4";
      rev = "labltk-8.06.4";
      sha256 = "03xwnnnahb2rf4siymzqyqy8zgrx3h26qxjgbp5dh1wdl7n02c7g";
    };
    "4.07" = mkNewParam {
      version = "8.06.5";
      rev = "1b71e2c6f3ae6847d3d5e79bf099deb7330fb419";
      sha256 = "02vchmrm3izrk7daldd22harhgrjhmbw6i1pqw6hmfmrmrypypg2";
    };
    _8_06_7 = mkNewParam {
      version = "8.06.7";
  