Persistent_env.Persistent_signaturetype t = {filename : string;Name of the file containing the signature.
*)cmi : Cmi_format.cmi_infos;}val load : (unit_name:string -> t option) Stdlib.refFunction used to load a persistent signature. The default is to look for the .cmi file in the load path. This function can be overridden to load it from memory, for instance to build a self-contained toplevel.