* use the one shiped by the latest CMake (ab379e5054aa792df9572078dcf95bddd75f7661)
* use the new policy to use the new find strategy.
* accomodate the vanilla FindPython3 module to Ceph by:
- dropping the `cmake_policy()` calls which set the policy not supported
by 3.16.
- `include (FindPackageHandleStandardArgs)` without specifying the
relative path.
- dropping the `HANDLE_VERSION_RANGE` from `FindPackageHandleStandardArgs()` call.
this option was introduced by CMake v3.19, see
https://cmake.org/cmake/help/latest/module/FindPackageHandleStandardArgs.html
but Ubuntu focal comes with CMake 3.16, which is our minimal required CMake version.
the new FindPython3 module from CMake:
* enables us to find the recent Python intepreter and development files up to
CPython 3.13.
* finds Python intepreter with the new `Python_FIND_STRATEGY`. the old and
default strategy always finds the most recent version with all specified name
and in all locations. so, if /usr/bin/python exists, it would accept, even
if it is a symlink to python3.9 and what we want is python3.6. the
new policy stops at the one which satisfies the constraints. this
helps us to address the problem of issue we have when recreating
the building system after the CMakeLists.txt is updated.
Fixes: https://tracker.ceph.com/issues/62428
Signed-off-by: Kefu Chai <tchaikov@gmail.com>
