Add possibility to store source files for interface targets

Add source files to the _qt_internal_target_sources property, when
running qt_internal_extend_target on interface libraries instead of
ignoring sources for CMake versions that don't support non-interface
properties. The property is not full-functional, but still allows to
execute internal routines on target sources.

Also add qt_internal_get_target_sources_property function that helps
to destinguish which property stores target sources.

Task-number: QTBUG-103196
Change-Id: I435c558090a24a7988f1a1c49f924dc195e72480
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

0 files changed, 0 insertions, 0 deletions