Make build warnings be errors

Change-Id: Ia9e32a36f5c0268c8e85ebf25168821d8ad0162d
diff --git a/media/audioserver/Android.mk b/media/audioserver/Android.mk
index b4a2e0f..5ce1798 100644
--- a/media/audioserver/Android.mk
+++ b/media/audioserver/Android.mk
@@ -54,4 +54,6 @@
 
 LOCAL_INIT_RC := audioserver.rc
 
+LOCAL_CFLAGS := -Werror -Wall
+
 include $(BUILD_EXECUTABLE)