fix gcc warning

Modified: branches/xmlbuildsystem/reactos/tools/rbuild/backend/backend.h

--- branches/xmlbuildsystem/reactos/tools/rbuild/backend/backend.h	2005-01-06 03:49:38 UTC (rev 12847)
+++ branches/xmlbuildsystem/reactos/tools/rbuild/backend/backend.h	2005-01-06 03:52:12 UTC (rev 12848)
@@ -18,6 +18,7 @@

 	protected:
 
 		Factory ( const std::string& name_ );

+		virtual ~Factory() {}

 
 		virtual Backend* operator() ( Project& ) = 0;