open Ocamlbuild_plugin
let includes =
  let open Pathname in
  let d = Array.to_list (readdir "include") in
  List.map (concat "include") d


let () =
  dispatch (function
             | After_rules ->
                dep ["ocaml";"compile";] includes;
                dep ["ocaml";"ocamldep"; ] includes;
                pflag ["ocaml";"compile";] "ppopt" (fun s -> S [A"-ppopt"; A (s)]);
                pflag ["ocaml";"ocamldep";] "ppopt" (fun s -> S [A"-ppopt"; A (s)]);
             | _ -> ()
           )