CMake: explicitly ask for ROOTEve component

ROOT no longer finds nlohmann_json unless we ask for the ROOTEve
component, so we ask for the ROOTEve component if the ROOTEve
component exists.  DDEve and one executable in UtilityApps depend on
this

CMakeLists.txt

@@ -126,6 +126,12 @@ dd4hep_configure_output( OUTPUT "${PROJECT_BINARY_DIR}" INSTALL "${CMAKE_INSTALL
 # Configure ROOT
 find_package (ROOT 6.08 REQUIRED CONFIG)
 DD4HEP_SETUP_ROOT_TARGETS()
+# ROOT no longer finds nlohmann_json unless we ask for the ROOTEve component, so we ask
+# for the ROOTEve component if the ROOTEve component exists.
+# DDEve and one executable in UtilityApps depend on this
+if(TARGET ROOT::ROOTEve)
+  find_package (ROOT REQUIRED COMPONENTS ROOTEve CONFIG)
+endif()
 
 # Configure BOOST
 find_package(Boost 1.49 REQUIRED)