[MAJOR] http: complete splitting of the remaining stages

The HTTP processing has been splitted into 7 steps, one of which
is not anymore HTTP-specific (content-switching). That way, it
becomes possible to use "use_backend" rules in TCP mode. A new
"use_server" directive should follow soon.
diff --git a/include/proto/proto_http.h b/include/proto/proto_http.h
index d70603c..35a216c 100644
--- a/include/proto/proto_http.h
+++ b/include/proto/proto_http.h
@@ -62,6 +62,7 @@
 int process_srv_data(struct session *t);
 int process_srv_conn(struct session *t);
 int http_wait_for_request(struct session *s, struct buffer *req, int an_bit);
+int http_process_req_common(struct session *s, struct buffer *req, int an_bit, struct proxy *px);
 int http_process_request(struct session *t, struct buffer *req, int an_bit);
 int http_process_tarpit(struct session *s, struct buffer *req, int an_bit);
 int http_process_request_body(struct session *s, struct buffer *req, int an_bit);