qdoc is built for host, so lib selection needs to match that.

Task-number: QTBUG-64982
Change-Id: I6c86052b8dcb4966c3faa5bc43bcd373f093ccc4
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>