From David Spilling, fix for VS6.0 build.
From David Spilling, fix for VS6.0 build.


ntoand/osg,omega-hub/osg,artoolkit/osg,XiaoCC/osg,stmh/osg,artoolkit/osg,XiaoCC/osg,stmh/osg,XiaoCC/osg,ghub/osg,omega-hub/osg,stmh/osg,ntoand/osg,koshman86/osg,XiaoCC/osg,artoolkit/osg,omega-hub/osg,ntoand/osg,koshman86/osg,ghub/osg,omega-hub/osg,artoolkit/osg,stmh/osg,ghub/osg,stmh/osg,ghub/osg,XiaoCC/osg,koshman86/osg,koshman86/osg,ntoand/osg