CMAKE_SYSTEM ------------ Composite name of operating system CMake is compiling for. This variable is the composite of :variable:`CMAKE_SYSTEM_NAME` and :variable:`CMAKE_SYSTEM_VERSION`, e.g. ``${CMAKE_SYSTEM_NAME}-${CMAKE_SYSTEM_VERSION}``. If :variable:`CMAKE_SYSTEM_VERSION` is not set, then this variable is the same as :variable:`CMAKE_SYSTEM_NAME`.