CMAKE_SYSTEM_ENVIRONMENT_ID

Added in version 4.5.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Externally-defined environment identifier that is cached. The value is not interpreted by cmake(1) and is a hint about the state of the environment during the first configure. When the value changes, cmake(1) by default emits a warning to the user indicating that the environment has changed and introspection results may be out of date.

The default warning behavior can be modified by setting CMAKE_SYSTEM_ENVIRONMENT_ACTION.