JDD: Change scope of DD_Ref and DD_Deref to "package" (to allow calls from DebugJDD)

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@11373 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/jdd/JDD.java

@@ -45,8 +45,8 @@ public class JDD
 	private static native void DD_SetCUDDMaxMem(long max_mem);
 	private static native void DD_SetCUDDEpsilon(double epsilon);
 	private static native void DD_CloseDownCUDD(boolean check);
-	private static native void DD_Ref(long dd);
-	private static native void DD_Deref(long dd);
+	static native void DD_Ref(long dd);
+	static native void DD_Deref(long dd);
 	private static native void DD_PrintCacheInfo();
 	private static native boolean DD_GetErrorFlag();
 	// dd_basics