Definition funsig2signature (s : funsig) cc : signature :=
  mksignature (map typ_of_type (map snd (fst s))) (opttyp_of_type (snd s)) cc.(* NOTE.   ext_link: Strings.String.string -> ident
   represents the mapping from the _name_ of an external function
  (an ASCII string) to the [ident] that's used to represent it in this program module.
  That mapping can be computed from the prog_defs component of the Clight.program
  produced by clightgen.
*)

Definition ef_id_sig (ext_link: Strings.String.string -> ident) ef :=
  match ef with EF_external id sig => Some (ext_link id, sig) | _ => None end.Definition symb2genv_upper_bound (s: PTree.t block) : block :=
  Pos.succ (fold_right Pos.max  1%positive (map snd (PTree.elements s))).Definition symb2genv (ge_s: injective_PTree block) : genv.

Lemma oi_eq_dec : forall a a' : option (ident * signature), { a = a' } + { a <> a' }.