Use find_package for DD4hep

src/detectors/pid/sdet/CMakeLists.txt

 cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
 
-#find_package ( DD4hep REQUIRED )
+find_package ( DD4hep REQUIRED )
 #include ( ${DD4hep_DIR}/cmake/DD4hep.cmake )
-include ( ${DD4hep_DIR}/cmake/DD4hepBuild.cmake )
+#include ( ${DD4hep_DIR}/cmake/DD4hepBuild.cmake )
 
 dd4hep_configure_output()
 dd4hep_set_compiler_flags()