CMP0001ΒΆ
CMAKE_BACKWARDS_COMPATIBILITY should no longer be used.
The 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
3.25.0-rc2 warns when the policy is not set and uses OLD behavior. Use
the cmake_policy() command to set it to OLD or NEW explicitly.
Note
The OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.