-extern BOOL transport_headers_send(address_item *, int, uschar *, uschar *,
- BOOL (*)(int, uschar *, int, BOOL), BOOL, rewrite_rule *, int);
-extern BOOL transport_write_message(address_item *, int, int, int, uschar *,
- uschar *, uschar *, uschar *, rewrite_rule *, int);
+extern BOOL transport_headers_send(transport_ctx *,
+ BOOL (*)(transport_ctx *, uschar *, int));
+extern void transport_show_supported(FILE *);
+extern BOOL transport_write_message(transport_ctx *, int);