CMP0001
-------

CMAKE_BACKWARDS_COMPATIBILITY should no longer be used.

The OLD behavior is to check CMAKE_BACKWARDS_COMPATIBILITY and present
it to the user.  The NEW behavior is to ignore
CMAKE_BACKWARDS_COMPATIBILITY completely.

In CMake 2.4 and below the variable CMAKE_BACKWARDS_COMPATIBILITY was
used to request compatibility with earlier versions of CMake.  In
CMake 2.6 and above all compatibility issues are handled by policies
and the cmake_policy command.  However, CMake must still check
CMAKE_BACKWARDS_COMPATIBILITY for projects written for CMake 2.4 and
below.

This policy was introduced in CMake version 2.6.0.  CMake version
|release| warns when the policy is not set and uses OLD behavior.  Use
the cmake_policy command to set it to OLD or NEW explicitly.