CLANG_FLAGS += -Werror=ignored-optimization-argument
CLANG_FLAGS += -Werror=option-ignored
CLANG_FLAGS += -Werror=unused-command-line-argument
-KBUILD_CFLAGS += $(CLANG_FLAGS)
-KBUILD_AFLAGS += $(CLANG_FLAGS)
+KBUILD_CPPFLAGS += $(CLANG_FLAGS)
export CLANG_FLAGS