Declare CLHEP and Geant4 headers as "SYSTEM" headers

LHCbG4Tests/G4SamplingCaloTest/CMakeLists.txt

@@ -5,7 +5,7 @@ gaudi_depends_on_subdirs(LHCbG4PhysLists)
 
 find_package(CLHEP REQUIRED)
 
-include_directories(${CMAKE_INSTALL_PREFIX}/include)
+include_directories(SYSTEM ${CMAKE_INSTALL_PREFIX}/include ${CLHEP_INCLUDE_DIRS})
 link_directories(${CMAKE_INSTALL_PREFIX}/lib)
 
 set(Geant4_LIBRARIES
@@ -25,7 +25,4 @@ gaudi_add_executable(G4SamplingCaloTest
 
 add_dependencies(G4SamplingCaloTest Geant4)
 
-# Dirty fix to disable the pesky warning
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-suggest-override")
-
 gaudi_install_scripts()