It can actually be null rather than undefined. We need to generate a
separate check for that and output the correct error messages.
Amends commit 05f56d7c78
Change-Id: Ia795e31805181640cd5be19359af51067d3fc8d6
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>