Enable Proguard.
diff --git a/Android.mk b/Android.mk
index 04706c3..7dba7b5 100644
--- a/Android.mk
+++ b/Android.mk
@@ -7,4 +7,6 @@
 
 LOCAL_PACKAGE_NAME := AlarmClock
 
+LOCAL_PROGUARD_ENABLED := full
+
 include $(BUILD_PACKAGE)