When checking the activeAction() in a slot connected to aboutToHide() for a QMenu then it will give 0 on Mac in Carbon

When checking the activeAction() in a slot connected to aboutToHide() for a QMenu then it will return a null action on Mac in Carbon.

Attached is an example (2nd patch.diff) that reproduces this in two separate cases (a context menu and via a menu in the menubar) with a patch that solves both cases. However when using the patch to solve it for the menu in the menubar case then aboutToHide() has to be connected to a slot by a queued connection to ensure the active action gets updated before the menu is hidden.