diff --git a/core/binary.mk b/core/binary.mk
index 9181699..e225edb 100644
--- a/core/binary.mk
+++ b/core/binary.mk
@@ -278,7 +278,7 @@
 # in the exception project list.
 ifeq ($(my_clang),false)
     ifeq ($(call find_in_local_clang_exception_projects,$(LOCAL_MODULE_MAKEFILE)),)
-        $(warning $(LOCAL_MODULE_MAKEFILE): $(LOCAL_MODULE): warning: LOCAL_CLANG is set to false)
+        $(error $(LOCAL_MODULE_MAKEFILE): $(LOCAL_MODULE): LOCAL_CLANG is set to false)
     endif
 endif
 
diff --git a/core/clang/config.mk b/core/clang/config.mk
index b31e419..7113892 100644
--- a/core/clang/config.mk
+++ b/core/clang/config.mk
@@ -149,6 +149,7 @@
   bionic/tests/ \
   device/huawei/angler/ \
   device/lge/bullhead/ \
+  external/gentoo/integration/ \
   external/valgrind/ \
   hardware/qcom/ \
   $(INTERNAL_LOCAL_CLANG_EXCEPTION_PROJECTS)