CMP0034

The utility_source() command should not be called.

This command was introduced in March 2001 to help build executables used to generate other files. This approach has long been replaced by add_executable() combined with add_custom_command().

CMake >= 3.0 prefer that this command never be called. The OLD behavior for this policy is to allow the command to be called. The NEW behavior for this policy is to issue a FATAL_ERROR when the command is called.

This policy was introduced in CMake version 3.0. CMake version 3.19.0-rc3 warns when the policy is not set and uses OLD behavior. Use the cmake_policy() command to set it to OLD or NEW explicitly.