CMake: Clean up logic to prepare building pure QML modules

Make sure we don't create bogus typeinfo entries, do create a target if
there are no C++ files, and do install created targets.

This way we do build the qmlcachegen-created files and link them into a
library which is subsequently deployed. It's not a real plugin, though,
and we need to specially handle this in QML. That's material for a
separate change.

Change-Id: I516d4611b6041a23489ce57df38dd83114dcc5de
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions