Default for CMake Policy
CMP<NNNN> when it is otherwise left unset.
cmake_policy(VERSION) by default leave policies introduced after
the given version unset. Set
NEW to specify the default for policy
is the policy number.
This variable should not be set by a project in CMake code as a way to
set its own policies; use
cmake_policy(SET) instead. This
variable is meant to externally set policies for which a project has
not itself been updated:
Users running CMake may set this variable in the cache (e.g.
-DCMAKE_POLICY_DEFAULT_CMP<NNNN>=<OLD|NEW>). Set it to
OLDto quiet a policy warning while using old behavior or to
NEWto try building the project with new behavior.
Projects may set this variable before a call to
add_subdirectory()that adds a third-party project in order to set its policies without modifying third-party code.