added Gtk::gtk_widget_get_allocation with proper #defines to use either direct accessor or gtk_widget_get_allocation.
added Gtk::gtk_widget_get_allocation with proper #defines to use either direct accessor or gtk_widget_get_allocation.

KDE/oxygen-gtk,blueshell-next/carbon-gtk,blue-shell/carbon-gtk,blue-shell/carbon-gtk,blueshell-next/carbon-gtk,KDE/oxygen-gtk