Note how to write CMP0022 compatible code with CMake 2.8.9.

This has come up on the mailing list, and various other places.

Help/policy/CMP0022.rst

@@ -22,6 +22,10 @@ downstream users of CMake versions older than 2.8.12.  The
 target_link_libraries command will no longer populate the properties
 matching LINK_INTERFACE_LIBRARIES(_<CONFIG>)? if this policy is NEW.
 
+Warning-free future-compatible code which works with CMake 2.8.9 onwards
+can be written by using the ``LINK_PRIVATE`` and ``LINK_PUBLIC`` keywords
+of :command:`target_link_libraries`.
+
 The OLD behavior for this policy is to ignore the
 INTERFACE_LINK_LIBRARIES property for in-build targets.  The NEW
 behavior for this policy is to use the INTERFACE_LINK_LIBRARIES