This establishes that linking is used to propagate usage-requirements
between targets in CMake code. The use of the target_link_libraries
command as the API for this is chosen because introducing a new command
would introduce confusion due to multiple commands which differ only in
a subtle way.
This means for example, that consumers can use:
target_link_libraries(foo ${QT_QTGUI_LIBRARIES})
instead of also needing to specify all 'public' dependencies:
target_link_libraries(foo ${QT_QTGUI_LIBRARIES} ${QT_QTCORE_LIBRARIES} )
when using the IMPORTED targets. Also populate the
IMPORTED_LINK_DEPENDENT_LIBRARIES property so CMake can help the linker
find shared library dependencies.
Stephen Kelly