- Shared libs and executables with exports may now have
    explicit transitive link dependencies specified
  - Created LINK_INTERFACE_LIBRARIES and related properties
  - Exported targets get the interface libraries as their
    IMPORTED_LINK_LIBRARIES property.
  - The export() and install(EXPORT) commands now give
    an error when a linked target is not included since
    the user can change the interface libraries instead
    of adding the target.