GdkWindow: Iterate through seats' pointers/keyboards in older grab functions
GdkWindow: Iterate through seats' pointers/keyboards in older grab functions

Instead of using the GdkDeviceManager.

grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita