* Making an Android APK should now generally work with NDK r21.d and
Qt 5.15.1 and CMake 3.18 although some details might still need tweaking
* It is now supposed to be used within the NDK's toolchain instead of
CMake's built-in Android support (which makes problems with newer NDK
versions)
* The old way to lookup/pass variables is preserved so it should still
work with older Qt versions and CMake's built-in Android support
* Qt's own support for invoking androiddeployqt needed to be disabled
because it lead to CMake errors (see comment)
Martchus