x11_common: implement VOCTRL_BEGIN_DRAGGING

This allows begin-vo-dragging command to initialize a vo dragging request
for x11. The last mouse button press event is used for _NET_WM_MOVERESIZE.
The hard-coded left mouse button down trigger is scheduled to be removed
in a later commit.

1 files changed, 2 insertions, 0 deletions

diff --git a/video/out/x11_common.h b/video/out/x11_common.h
index d88c8899c8..8a3b145161 100644
--- a/video/out/x11_common.h
+++ b/video/out/x11_common.h
@@ -138,6 +138,8 @@ struct vo_x11_state {
     Window dnd_src_window;
 
     Atom icc_profile_property;
+
+    XEvent last_button_event;
 };
 
 bool vo_x11_init(struct vo *vo);