Merge changes from topic "pppolac"

* changes:
  mtpd: Use L2TP implementation from mainline kernel
  mtpd: l2tp: Fix endianness issues in log prints
  mtpd: Remove obsolete way of passing args to pppd
diff --git a/Android.bp b/Android.bp
index b865eec..064b0c8 100644
--- a/Android.bp
+++ b/Android.bp
@@ -25,6 +25,10 @@
         "liblog",
         "libnetd_client",
     ],
-    cflags: ["-DANDROID_CHANGES"],
+    cflags: [
+        "-DANDROID_CHANGES",
+        "-Wall",
+        "-Werror",
+    ],
     init_rc: ["mtpd.rc"],
 }