Enable strict warning checks and fix

Change-Id: Id401a937911eb418e93314812f2f7c2b5ecff8d6
diff --git a/media/common_time/Android.mk b/media/common_time/Android.mk
index 632acbc..aaa0db2 100644
--- a/media/common_time/Android.mk
+++ b/media/common_time/Android.mk
@@ -19,4 +19,6 @@
                           libutils \
                           liblog
 
+LOCAL_CFLAGS := -Wall -Werror
+
 include $(BUILD_SHARED_LIBRARY)