overlay: Always align widgets relative to the overlay
overlay: Always align widgets relative to the overlay

... not to the contained widget, which might not occupy the whole
overlay when an align mode is set.

davidgumberg/gtk,jadahl/gtk,davidgumberg/gtk,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,jigpu/gtk,jadahl/gtk,chergert/gtk,davidgumberg/gtk,jigpu/gtk,grubersjoe/adwaita,alexlarsson/gtk,jadahl/gtk,davidgumberg/gtk,alexlarsson/gtk,grubersjoe/adwaita,jadahl/gtk,jadahl/gtk,grubersjoe/adwaita,alexlarsson/gtk,davidgumberg/gtk,jigpu/gtk,chergert/gtk,grubersjoe/adwaita,chergert/gtk,davidgumberg/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jadahl/gtk,davidgumberg/gtk,jigpu/gtk,chergert/gtk,chergert/gtk,chergert/gtk,chergert/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk,jigpu/gtk,chergert/gtk,jadahl/gtk,alexlarsson/gtk,alexlarsson/gtk,alexlarsson/gtk,jigpu/gtk,alexlarsson/gtk,jadahl/gtk