Qt6 port:

* Constructor of QFontDatabase is deprecated, use static functions instead
* Fix QuantitySpinBox::selectNumber()
* Fix InputField::selectNumber()
* Make InputField::fixup() compatible with Qt6
* QFont::setWeight requires an enum now
* QInputEvent reuires a pointing device now
* QAbstractItemView::viewOptions() has been renamed to QAbstractItemView::initViewItemOption()

src/Gui/SpaceballEvent.cpp

@@ -30,7 +30,11 @@ using namespace Spaceball;
 int MotionEvent::MotionEventType = -1;
 int ButtonEvent::ButtonEventType = -1;
 
+#if QT_VERSION < QT_VERSION_CHECK(6,0,0)
 EventBase::EventBase(QEvent::Type event) : QInputEvent(static_cast<QEvent::Type>(event)), handled(false)
+#else
+EventBase::EventBase(QEvent::Type event) : QInputEvent(static_cast<QEvent::Type>(event), QPointingDevice::primaryPointingDevice()), handled(false)
+#endif
 {
 
 }