CMP0025 ------- Compiler id for Apple Clang is now ``AppleClang``. CMake 3.0 and above recognize that Apple Clang is a different compiler than upstream Clang and that they have different version numbers. CMake now prefers to present this to projects by setting the :variable:`CMAKE__COMPILER_ID` variable to ``AppleClang`` instead of ``Clang``. However, existing projects may assume the compiler id for Apple Clang is just ``Clang`` as it was in CMake versions prior to 3.0. Therefore this policy determines for Apple Clang which compiler id to report in the :variable:`CMAKE__COMPILER_ID` variable after language ```` is enabled by the :command:`project` or :command:`enable_language` command. The policy must be set prior to the invocation of either command. The OLD behavior for this policy is to use compiler id ``Clang``. The NEW behavior for this policy is to use compiler id ``AppleClang``. This policy was introduced in CMake version 3.0. Use the :command:`cmake_policy` command to set this policy to OLD or NEW explicitly. Unlike most policies, CMake version |release| does *not* warn by default when this policy is not set and simply uses OLD behavior. See documentation of the :variable:`CMAKE_POLICY_WARNING_CMP0025 >` variable to control the warning.