extern int parse_options_end(struct parse_opt_ctx_t *ctx);
-extern int parse_options_concat(struct option *dst, size_t, struct option *src);
+extern struct option *parse_options_concat(struct option *a, struct option *b);
/*----- some often used options -----*/
extern int parse_opt_abbrev_cb(const struct option *, const char *, int);
extern int parse_opt_tertiary(const struct option *, const char *, int);
extern int parse_opt_string_list(const struct option *, const char *, int);
extern int parse_opt_noop_cb(const struct option *, const char *, int);
+extern int parse_opt_unknown_cb(const struct option *, const char *, int);
extern int parse_opt_passthru(const struct option *, const char *, int);
extern int parse_opt_passthru_argv(const struct option *, const char *, int);