val fatal_error : Pp.t -> 'aval ensure : ext:string -> src:string -> tgt:string -> stringval ensure_exists : string -> unitval ensure_exists_with_prefix : 
  src:string ->
  tgt:string option ->
  src_ext:string ->
  tgt_ext:string ->
  string * stringval safe_chop_extension : string -> stringval ensure_no_pending_proofs : filename:string -> Vernacstate.t -> unit