FILE GLOB_RECURSE calls should not follow symlinks by default.
In CMake 2.6.1 and below,
file(GLOB_RECURSE) calls would follow
through symlinks, sometimes coming up with unexpectedly large result sets
because of symlinks to top level directories that contain hundreds of
thousands of files.
This policy determines whether or not to follow symlinks encountered
file(GLOB_RECURSE) call. The
OLD behavior for this
policy is to follow the symlinks. The
NEW behavior for this policy is not
to follow the symlinks by default, but only if
FOLLOW_SYMLINKS is given
as an additional argument to the
This policy was introduced in CMake version 2.6.2. CMake version
3.20.2 warns when the policy is not set and uses
OLD behavior. Use
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.