New in version 3.12.
In CMake 3.12 and above the
find_package(<PackageName>) command now
searches prefixes specified by the
variable and the
<PackageName>_ROOT environment variable.
Package roots are maintained as a stack so nested calls to all
commands inside find modules and config packages also search the roots as
prefixes. This policy provides compatibility with projects that have not been
updated to avoid using
<PackageName>_ROOT variables for other purposes.
OLD behavior for this policy is to ignore
NEW behavior for this policy is to use
This policy was introduced in CMake version 3.12. CMake version
3.26.1 warns when the policy is not set and uses
cmake_policy() command to set it to
OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.