Qt Charts fails to build for Android

When building Qt Charts (6.1.0 branch) for Android with NDK 21.3.6528147 the build will fail (at least in release mode) because of the following errors: [a result of -Werror,-Woverloaded-virtual]

qtbase/include/QtCharts/6.1.0/QtCharts\private/../../../../../../../qt6-6.1.0/qtcharts/src/charts/axis/chartaxiselement_p.h:70:18: error: 'ChartAxisElement::isEmpty' hides overloaded virtual function [-Werror,-Woverloaded-virtual] virtual bool isEmpty() = 0; ^ D:\Code\qt6-6.1.0-android-release\qtbase\include\QtWidgets\..\..\..\..\qt6-6.1.0\qtbase\src\widgets\graphicsview\qgraphicslayoutitem.h:97:18: note: hidden overloaded virtual function 'QGraphicsLayoutItem::isEmpty' declared here: different qualifiers ('const' vs unqualified) virtual bool isEmpty() const; ^ 1 error generated.

It's technically a warning, but since this is on by default it will cause issues for people, at least building for release which is what we would normally do for mobile platforms.