CMP0074ΒΆ
find_package() uses <PackageName>_ROOT variables.
In CMake 3.12 and above the find_package(<PackageName>) command now
searches prefixes specified by the <PackageName>_ROOT CMake
variable and the <PackageName>_ROOT environment variable.
Package roots are maintained as a stack so nested calls to all find_*
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.
The OLD behavior for this policy is to ignore <PackageName>_ROOT
variables. The NEW behavior for this policy is to use
<PackageName>_ROOT variables.
This policy was introduced in CMake version 3.12. CMake version
3.18.6 warns when the policy is not set and uses OLD behavior.
Use the cmake_policy() command to set it to OLD or NEW
explicitly.
Note
The OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.