Fixing deprecated usage of snd_ctl_add_slave
--- a/src/control.c
+++ b/src/control.c
@@ -571,7 +571,7 @@
 		ret = snd_ctl_add(card, control);
 		if (ret < 0)
 			return ret;
-		ret = snd_ctl_add_slave(vmaster, control);
+		ret = snd_ctl_add_follower(vmaster, control);
 		if (ret < 0)
 			return ret;
 		i++;