Use intnat, not int, to store closure keys.
Use intnat, not int, to store closure keys.

ocamllabs/ocaml-ctypes,yallop/ocaml-ctypes,whitequark/ocaml-ctypes,ocamllabs/ocaml-ctypes,whitequark/ocaml-ctypes,whitequark/ocaml-ctypes,yallop/ocaml-ctypes