Replace CMake command exec_program with execute_process
exec_program has been deprecated for quite some time and recent versions of CMake warn not to use it. See https://cmake.org/cmake/help/latest/policy/CMP0153.html
exec_program has been deprecated for quite some time and recent versions of CMake warn not to use it. See https://cmake.org/cmake/help/latest/policy/CMP0153.html