Use -Werror in external/libtextclassifier
am: 8a2c193de5

Change-Id: Iec09341c5767f969f8d2baf150a8b98714470c8d
diff --git a/Android.bp b/Android.bp
index a886a0c..0ca3b5f 100644
--- a/Android.bp
+++ b/Android.bp
@@ -12,6 +12,9 @@
         "util/hash/hash.cc"
     ],
     cflags: [
-        "-DNAMESPACE_FOR_HASH_FUNCTIONS=farmhash"
+        "-DNAMESPACE_FOR_HASH_FUNCTIONS=farmhash",
+        "-Wall",
+        "-Werror",
+        "-Wno-unused-function",
     ],
 }