MEDIUM: listener: Bind listeners on a thread subset if specified

If a "process" option with a thread set is used on the bind line, we use the
corresponding bitmask when the listener's FD is created.
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index fc4a519..3b353c6 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -334,7 +334,10 @@
 	/* the function for the accept() event */
 	fdtab[fd].iocb = listener->proto->accept;
 	fdtab[fd].owner = listener; /* reference the listener instead of a task */
-	fd_insert(fd, MAX_THREADS_MASK);
+	if (listener->bind_conf->bind_thread[relative_pid-1])
+		fd_insert(fd, listener->bind_conf->bind_thread[relative_pid-1]);
+	else
+		fd_insert(fd, MAX_THREADS_MASK);
 	return err;
 
  err_rename: