(* The Espec for odd is different from the Espec for even;
  the former has only "even" as an external function, and vice versa. *)
Definition Espec := add_funspecs NullExtension.Espec (ext_link_prog even.prog) Gprog.

Lemma all_funcs_correct: semax_func Vprog Gprog (prog_funct prog) Gprog.