[gtk/wip/exalm/hotspot-fix] wayland: Fix dnd hotspot movement

[Alexander Mikhaylenko <alexm src gnome org>]

commit 0a59429dc8768166e7674762ed743cc8a44740b1
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Thu Aug 27 04:04:48 2020 +0500

    wayland: Fix dnd hotspot movement
    
    _gdk_wayland_surface_offset_next_wl_buffer() moves the surface relatively
    to its current position, pass it a delta instead of new position.

 gdk/wayland/gdkdrag-wayland.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gdk/wayland/gdkdrag-wayland.c b/gdk/wayland/gdkdrag-wayland.c
index 05bf681717..de80afe020 100644
--- a/gdk/wayland/gdkdrag-wayland.c
+++ b/gdk/wayland/gdkdrag-wayland.c
@@ -137,7 +137,7 @@ gdk_wayland_drag_set_hotspot (GdkDrag *drag,
     return;
 
   _gdk_wayland_surface_offset_next_wl_buffer (drag_wayland->dnd_surface,
-                                             -hot_x, -hot_y);
+                                             prev_hot_x - hot_x, prev_hot_y - hot_y);
   gdk_surface_invalidate_rect (drag_wayland->dnd_surface, &damage_rect);
 }