Silence 694 warnings

And turn on -Wall -Werror.

Test: builds
Change-Id: I372f69715f7a5ee5d6f72bb9f766f19d5602f492
diff --git a/Android.bp b/Android.bp
index 3123189..b45a525 100644
--- a/Android.bp
+++ b/Android.bp
@@ -39,6 +39,12 @@
         "-D__HAVE_BUILTIN_BSWAP16__",
         "-D__HAVE_BUILTIN_BSWAP32__",
         "-D__HAVE_BUILTIN_BSWAP64__",
+
+        "-Wno-unused-parameter",
+        "-Wno-sign-compare",
+        "-Wno-pointer-arith",
+        "-Wall",
+        "-Werror",
     ],
     shared_libs: ["libnfnetlink"],
 }