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 This approach has long been replaced by add_executable() combined with add_custom_command().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 3.15.7 warns when the policy is not set and uses OLD behavior. Use the cmake_policy() command to set it to OLD or NEW explicitly.