Issue a deprecation warning on calls to `cmake_minimum_required` or
`cmake_policy` that set policies based on versions older than 3.5.
Note that the effective policy version includes `...<max>` treatment.
Update the check from commit 5845c218d7 (Deprecate compatibility with
CMake versions older than 2.8.12, 2020-06-12, v3.19.0-rc1~629^2).
For policy-specific tests, use the version before the policy was
introduced. Otherwise, use 3.5 where possible.
Also, remove `cmake_minimum_required()` and `project()` calls from
individual cases where they are handled by `CMakeLists.txt`.
When `$<TARGET_PROPERTY:tgt,prop>` is used in an `INTERFACE_*` target
property for usage requirements, it may be evaluated in the context of a
dependent target in another directory. Look up the `tgt` name in the
directory of the target whose property holds the expression so that
imported targets isolated to that directory are visible.
Fixes: #24163
The existing cases all need to enable a language. Move this out of the
`CMakeLists.txt` file and into the individual cases to make room for
other cases that may not need this.
Brad King