diff --git a/core/soong_java_prebuilt.mk b/core/soong_java_prebuilt.mk
index 96ff376..3773c07 100644
--- a/core/soong_java_prebuilt.mk
+++ b/core/soong_java_prebuilt.mk
@@ -40,21 +40,26 @@
     $(intermediates.COMMON)/jacoco-report-classes.jar)
 endif
 
-ifdef LOCAL_SOONG_EXPORT_PROGUARD_FLAGS
-  $(eval $(call copy-one-file,$(LOCAL_SOONG_EXPORT_PROGUARD_FLAGS),\
-    $(intermediates.COMMON)/export_proguard_flags))
-  $(call add-dependency,$(LOCAL_BUILT_MODULE),\
-    $(intermediates.COMMON)/export_proguard_flags)
-endif
-
 ifdef LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE
-my_res_package := $(intermediates.COMMON)/package-res.apk
+  my_res_package := $(intermediates.COMMON)/package-res.apk
 
-$(my_res_package): $(LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE)
+  $(my_res_package): $(LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE)
 	@echo "Copy: $@"
 	$(copy-file-to-target)
 
-$(call add-dependency,$(LOCAL_BUILT_MODULE),$(my_res_package))
+  $(call add-dependency,$(LOCAL_BUILT_MODULE),$(my_res_package))
+
+  my_proguard_flags := $(intermediates.COMMON)/export_proguard_flags
+  $(my_proguard_flags): $(LOCAL_SOONG_EXPORT_PROGUARD_FLAGS)
+	@echo "Export proguard flags: $@"
+	rm -f $@
+	touch $@
+	for f in $+; do \
+		echo -e "\n# including $$f" >>$@; \
+		cat $$f >>$@; \
+	done
+
+  $(call add-dependency,$(LOCAL_BUILT_MODULE),$(my_proguard_flags))
 
 endif # LOCAL_SOONG_RESOURCE_EXPORT_PACKAGE