It doesn't seem like that it is being used anymore, except an instance
in pro2cmake which I replaced by NO_GENERATE_METATYPES.
Change-Id: I135cf47e6041e98b354fb684f0079dad30689dea
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit b171abe69533a83c5b6fea51807da3ad45a1d3f3)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>