anchor.diff: -{ stdenv, fetchurl, ocaml, findlib, ocamlbuild, opam }:
  +{ stdenv, fetchurl, ocaml, findlib, ocamlbuild, opaline }:
   
   let
     inherit (stdenv.lib) getVersion versionAtLeast;
  
positive.code: 
    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}
    '';
  
    meta = with stdenv.lib; {
      description = "Basic types for computer graphics in OCaml";
  
negative.code:     sha256 = "0czj41sr8jsivl3z8wyblf9k971j3kx2wc3s0c1nhzcc8allg9i2";
    };
  
    buildInputs = [ ocaml findlib ocamlbuild opaline ];
  
    createFindlibDestdir = true;
  
  