diff --git a/libnativebridge/Android.mk b/libnativebridge/Android.mk
index 6c2e43e..83169eb 100644
--- a/libnativebridge/Android.mk
+++ b/libnativebridge/Android.mk
@@ -13,7 +13,7 @@
 LOCAL_SHARED_LIBRARIES := liblog
 LOCAL_CLANG := true
 LOCAL_CPP_EXTENSION := .cc
-LOCAL_CFLAGS := -Werror -Wall
+LOCAL_CFLAGS += -Werror -Wall
 LOCAL_CPPFLAGS := -std=gnu++11 -fvisibility=protected
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
@@ -30,11 +30,11 @@
 LOCAL_SHARED_LIBRARIES := liblog
 LOCAL_CLANG := true
 LOCAL_CPP_EXTENSION := .cc
-LOCAL_CFLAGS := -Werror -Wall
+LOCAL_CFLAGS += -Werror -Wall
 LOCAL_CPPFLAGS := -std=gnu++11 -fvisibility=protected
 LOCAL_LDFLAGS := -ldl
 LOCAL_MULTILIB := both
 
 include $(BUILD_HOST_SHARED_LIBRARY)
 
-include $(LOCAL_PATH)/tests/Android.mk
\ No newline at end of file
+include $(LOCAL_PATH)/tests/Android.mk