Mark the include directories of clang and llvm as system.

interpreter/CMakeLists.txt

@@ -459,10 +459,7 @@ if (builtin_cling)
   if(MSVC)
     set(CLING_CXXFLAGS "-DNOMINMAX -D_XKEYCHECK_H")
   else()
-    set(CLING_CXXFLAGS " -fvisibility=hidden -Wno-shadow -fno-strict-aliasing -Wno-unused-parameter -Wwrite-strings -Wno-long-long ")
-  endif()
-  if (CMAKE_COMPILER_IS_GNUCXX)
-    string(APPEND CLING_CXXFLAGS " -Wno-missing-field-initializers")
+    set(CLING_CXXFLAGS " -fvisibility=hidden -fno-strict-aliasing -Wwrite-strings ")
   endif()
 
   string(APPEND CMAKE_CXX_FLAGS ${CLING_CXXFLAGS})

interpreter/cling/CMakeLists.txt

@@ -330,7 +330,7 @@ macro(set_cling_windows_version_resource_properties name)
   endif()
 endmacro()
 
-include_directories(BEFORE ${LLVM_INCLUDE_DIRS} ${CLANG_INCLUDE_DIRS})
+include_directories(BEFORE SYSTEM ${LLVM_INCLUDE_DIRS} ${CLANG_INCLUDE_DIRS})
 
 macro(add_cling_library name)
   cmake_parse_arguments(ARG