extern int verify_check_header_names_ascii(uschar **);
extern int verify_check_host(uschar **);
extern int verify_check_notblind(void);
-extern int verify_check_given_host(uschar **, host_item *);
+extern int verify_check_given_host(const uschar **, const host_item *);
extern int verify_check_this_host(const uschar **, unsigned int *,
const uschar*, const uschar *, const uschar **);
extern address_item *verify_checked_sender(uschar *);