compilation fixes when no OSG_GL_DISPLAYLISTS_AVAILABLE
compilation fixes when no OSG_GL_DISPLAYLISTS_AVAILABLE

scrawl/osg,scrawl/osg,openscenegraph/osg,scrawl/osg,jtorresfabra/osg,openscenegraph/osg,openscenegraph/osg,scrawl/osg,marchelbling/osg,jtorresfabra/osg,jtorresfabra/osg,marchelbling/osg,marchelbling/osg,marchelbling/osg,openscenegraph/osg,jtorresfabra/osg