diff --git a/core/java.mk b/core/java.mk
index 5772ba2..71bed38 100644
--- a/core/java.mk
+++ b/core/java.mk
@@ -726,6 +726,7 @@
 endif # !USE_R8
 
 else  # LOCAL_PROGUARD_ENABLED not defined
+proguard_flag_files :=
 full_classes_proguard_jar := $(full_classes_pre_proguard_jar)
 endif # LOCAL_PROGUARD_ENABLED defined