Add -Werror flag to catch more warnings and errors

Change-Id: I9c39ba24578931944aae8182918ed48a2e82eb39
diff --git a/native/Android.mk b/native/Android.mk
index c8342e3..4727b1e 100644
--- a/native/Android.mk
+++ b/native/Android.mk
@@ -3,6 +3,11 @@
 
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/src
 
+LOCAL_CFLAGS += -Werror -Wall
+
+# To suppress compiler warnings for unused variables/functions used for debug features etc.
+LOCAL_CFLAGS += -Wno-unused-parameter -Wno-unused-function
+
 LOCAL_SRC_FILES := \
     jni/com_android_inputmethod_keyboard_ProximityInfo.cpp \
     jni/com_android_inputmethod_latin_BinaryDictionary.cpp \