Libraries linked may not have leading or trailing whitespace.
CMake versions 2.4 and below silently removed leading and trailing whitespace from libraries linked with code like
target_link_libraries(myexe " A ")
This could lead to subtle errors in user projects.
The OLD behavior for this policy is to silently remove leading and trailing whitespace. The NEW behavior for this policy is to diagnose the existence of such whitespace as an error. The setting for this policy used when checking the library names is that in effect when the target is created by an add_executable or add_library command.
This policy was introduced in CMake version 2.6.0. CMake version 3.6.2 warns when the policy is not set and uses OLD behavior. Use the cmake_policy command to set it to OLD or NEW explicitly.
OLD behavior of a policy is
deprecated by definition
and may be removed in a future version of CMake.