--- pdf2djvu-0.7.4/system.hh	2010-06-12 22:20:36.000000000 +0200
+++ pdf2djvu-0.7.4/system.hh	2011-03-15 14:58:35.000000000 +0100
@@ -162,6 +162,8 @@ private:
 public:
   explicit ExistingFile(const std::string &name);
   ExistingFile(const Directory& directory, const std::string &name);
+  virtual ~ExistingFile() throw ()
+  { }
 };
 
 #if WIN32