getopt_old.m:027: In clause for predicate `main'/2:
getopt_old.m:027:   in argument 2 of call to predicate `io.format'/4:
getopt_old.m:027:   in list element #0:
getopt_old.m:027:   in unification of argument
getopt_old.m:027:   and term `s(ErrorMsg)':
getopt_old.m:027:   type error in argument of functor `s'/1.
getopt_old.m:027:   Argument 1 (ErrorMsg) has type
getopt_old.m:027:     getopt.option_error(getopt_old.option),
getopt_old.m:027:   expected type was
getopt_old.m:027:     string.
getopt_old.m:027:   One possible reason for the error is that the signatures of
getopt_old.m:027:   the option processing predicates in the `getopt' module
getopt_old.m:027:   have changed recently. Errors are now returned in a
getopt_old.m:027:   structured form, which can be converted to a string by
getopt_old.m:027:   calling the `option_error_to_string' function.