Index: ocaml_specific.ml
===================================================================
--- ocaml_specific.ml	(revision 15833)
+++ ocaml_specific.ml	(working copy)
@@ -530,6 +530,21 @@
 flag [ "ocaml" ; "menhir" ; "explain" ] (S[A "--explain"]);;
 flag [ "ocaml" ; "menhir" ; "infer" ] (S[A "--infer"]);;

+(* Define two ocamlbuild flags [only_tokens] and [external_tokens(Foo)]
+   which correspond to menhir's [--only-tokens] and [--external-tokens Foo].
+   When they are used, these flags should be passed both to [menhir] and to
+   [menhir --raw-depend]. *)
+let () =
+  List.iter (fun mode ->
+
+    flag [ mode; "only_tokens" ] (S[A "--only-tokens"]);
+
+    pflag [ mode ] "external_tokens" (fun name ->
+      S[A "--external-tokens"; A name]
+    )
+
+  ) [ "menhir"; "menhir_ocamldep" ]
+
 flag ["ocaml"; "ocamllex"] (atomize !Options.ocaml_lexflags);;

 (* Tell ocamllex to generate ml code *)