Test transitive includes from setting the LINK_LIBRARIES property.

Commit b8259c3d (Centralize maintenance of usage requirement include
directories, 2013-04-29) changed the handling of the property.
Previously setting the property directly instead of via
target_link_libraries would not result in transitive include
directory handling.
Test that linking using the debug keyword to tll works.
Merge topic 'fix-per-config-tll-include-dirs' into next

e9a2a67 Test that linking using the debug keyword to tll works.
20104ab Test transitive includes from setting the LINK_LIBRARIES property.