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
Please be advised that registry.cern.ch registry (Registry Service) will be unavailable next Monday, March 10th starting at 08:00h (Geneva time) for a short period of time. This may cause temporary disruptions to your workflows. Further information: OTG0154905
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