diff --git a/ocamlbuild/ocaml_specific.ml b/ocamlbuild/ocaml_specific.ml
index 2b2062fe5..cc8f29306 100644
--- a/ocamlbuild/ocaml_specific.ml
+++ b/ocamlbuild/ocaml_specific.ml
@@ -488,6 +488,12 @@ let camlp4_flags camlp4s =
 
 camlp4_flags ["camlp4o"; "camlp4r"; "camlp4of"; "camlp4rf"; "camlp4orf"; "camlp4oof"];;
 
+let p4_series =  ["camlp4o"; "camlp4r"; "camlp4of"; "camlp4rf"; "camlp4orf"; "camlp4oof"];;
+let p4_opt_series = List.map (fun f -> f ^ ".opt") p4_series;;
+
+camlp4_flags p4_series;;
+camlp4_flags p4_opt_series;;
+
 let camlp4_flags' camlp4s =
   List.iter begin fun (camlp4, flags) ->
     flag ["ocaml"; "pp"; camlp4] flags