add scroll button option

This commit introduces a scroll_button option, which is intended to be
used with scroll_method. Now user can edit his sway config and add an
scroll_button option to device section.

1 files changed, 1 insertions, 0 deletions

diff --git a/include/sway/config.h b/include/sway/config.h
index 99575274..75acd4f2 100644
--- a/include/sway/config.h
+++ b/include/sway/config.h
@@ -75,6 +75,7 @@ struct input_config {
 	float pointer_accel;
 	int repeat_delay;
 	int repeat_rate;
+	int scroll_button;
 	int scroll_method;
 	int send_events;
 	int tap;