gtk/gtk.go
func (v *Calendar) UnmarkDay(day uint) {
	C.gtk_calendar_unmark_day(v.native(), C.guint(day))
}
func (v *Calendar) UnmarkDay(day uint) {
	C.gtk_calendar_unmark_day(v.native(), C.guint(day))
}
// UnmarkDay is a wrapper around gtk_calendar_unmark_day().