The Wayland protocol specifies output transform rotations to be
counterclockwise and applied to the surface. Previously, wlroots
copied Weston and incorrectly made rotations act clockwise on
surfaces. This commit fixes that.
This change will break compositors which expect transform rotations
to be clockwise, and the rare applications that make use of surface
transforms.
If box->width/height is <= 0, the box doesn't contain any points, and so
there is no closest point. wlr_box_closest_point should return NAN in this
case.
In addition, we need to handle empty boxes in a few other
output-layout-related places, because outputs can have size 0x0 when
they are created or destroyed.
