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.
This is a partial revert of commit 77cecb77 (Add includes and compile
definitions with target_link_libraries., 2012-11-05).
As the interface includes and defines are now determined by the link
closure, there is no need to populate the corresponding properties
explicitly.
Otherwise, we get a separate IncludeDirectoriesEntry for each include,
and that causes unnecessary and confusing splitting in the output when
debugging the INCLUDE_DIRECTORIES property.
Stephen Kelly