anchor.diff:  
     buildPhase = "ocaml pkg/build.ml native=true native-dynlink=true";
   
  -  installPhase = ''
  -    opam-installer --script --prefix=$out ${pname}.install | sh
  -    ln -s $out/lib/${pname} $out/lib/ocaml/${getVersion ocaml}/site-lib/${pname}
  -  '';
  +  installPhase = "opaline -libdir $OCAMLFIND_DESTDIR";
   
     meta = with stdenv.lib; {
       description = "Basic types for computer graphics in OCaml";
  
positive.code: { stdenv, fetchurl, ocaml, findlib, ocamlbuild, opam }:
  
  let
    inherit (stdenv.lib) getVersion versionAtLeast;
  
negative.code:     sha256 = "0czj41sr8jsivl3z8wyblf9k971j3kx2wc3s0c1nhzcc8allg9i2";
    };
  
    buildInputs = [ ocaml findlib ocamlbuild opaline ];
  
    createFindlibDestdir = true;
  
  