Policy CMP0009 warning when symlink-installing a directory that contains a symlink

[Roboterbastler]

I have some packages that print a cmake policy warning when I try to install directories:

CMake Warning (dev) at ament_cmake_symlink_install/ament_cmake_symlink_install.cmake:62 (file):
  Policy CMP0009 is not set: FILE GLOB_RECURSE calls should not follow
  symlinks by default.  Run "cmake --help-policy CMP0009" for policy details.
  Use the cmake_policy command to set the policy and suppress this warning.
Call Stack (most recent call first):
  ament_cmake_symlink_install/ament_cmake_symlink_install.cmake:314 (ament_cmake_symlink_install_directory)
  cmake_install.cmake:46 (include)
This warning is for project developers.  Use -Wno-dev to suppress it.

As far as I know there is no way to fix this warning from my side, the policy should probably be set inside ament_cmake_core (I would say it should be set to NEW in order not to follow the links).

A minimal example package setup to show this warning looks as follows:

• CMakeLists.txt
• package.xml
• config
  • some_dir
    • foo.yaml
  • alias_dir --> some_dir

CMakeLists.txt like this:

cmake_minimum_required(VERSION 3.8)
project(test_pkg)
find_package(ament_cmake REQUIRED)
install(
  DIRECTORY config
  DESTINATION share/${PROJECT_NAME}
)
ament_package()

Then build with --symlink-install.

(version: ROS 2 Jazzy)