external scrub_device : t -> string -> unit = "ocaml_guestfs_scrub_device"
external scrub_file : t -> string -> unit = "ocaml_guestfs_scrub_file"
external scrub_freespace : t -> string -> unit = "ocaml_guestfs_scrub_freespace"
+external mkdtemp : t -> string -> string = "ocaml_guestfs_mkdtemp"