Center the Wayland diagnostic cursor on its actual pointer hotspot and
preserve it while cursor themes are reloaded for output-scale changes.
Round fractional guest positions to the nearest logical pixel instead of
biasing synchronization toward the top-left corner.
Resynchronize the hardware pointer when a cursor shape changes its
hotspot. Only perform the extra synchronization when the hotspot
actually changes, and update the basic-mode projection at the same time.