Made USE_AGL=yes the default under OSX.
Made USE_AGL=yes the default under OSX.


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