New in version 3.1.
Reject source and build dirs in installed
CMake 3.0 and lower allowed subdirectories of the source directory or build
directory to be in the
installed and exported targets, if the directory was also a subdirectory of
the installation prefix. This makes the installation depend on the
existence of the source dir or binary dir, and the installation will be
broken if either are removed after installation.
See Include Directories and Usage Requirements for more on specifying include directories for targets.
OLD behavior for this policy is to export the content of the
INTERFACE_INCLUDE_DIRECTORIES with the source or binary
NEW behavior for this
policy is to issue an error if such a directory is used.
This policy was introduced in CMake version 3.1.
CMake version 3.19.8 warns when the policy is not set and uses
OLD behavior. Use the
cmake_policy() command to set it
OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.