extern void transport_update_waiting(host_item *, uschar *);
extern BOOL transport_write_block(int, uschar *, int);
extern BOOL transport_write_string(int, const char *, ...);
-extern BOOL transport_headers_send(address_item *, int, transport_instance *,
- BOOL (*)(int, uschar *, int, unsigned),
- BOOL);
+extern BOOL transport_headers_send(int, transport_ctx *,
+ BOOL (*)(int, transport_ctx *, uschar *, int));
extern BOOL transport_write_message(int, transport_ctx *, int);
extern void tree_add_duplicate(uschar *, address_item *);
extern void tree_add_nonrecipient(uschar *);