- CMake 1.8 and below did not do the check but could get in
    infinite loops due to the local generate step.
  - CMake 2.0 added the check but failed to perform it in directories
    with no targets (see bug #678).
  - CMake 2.2 removed the local generate which fixed the problem but
    did not remove the check.
  - Between CMake 2.4 and 2.6.0rc6 the check was fixed to work even
    when no targets appear in a directory (see bug #6923).
  - Bottom line: the check is no longer needed.