Fixed Clang warnings related to external dependencies
Fixed Clang warnings related to external dependencies

tomasthoresen/osg,openscenegraph/osg,artoolkit/osg,marchelbling/osg,openscenegraph/osg,scrawl/osg,jtorresfabra/osg,tomasthoresen/osg,scrawl/osg,marchelbling/osg,artoolkit/osg,tomasthoresen/osg,marchelbling/osg,scrawl/osg,jtorresfabra/osg,openscenegraph/osg,scrawl/osg,openscenegraph/osg,tomasthoresen/osg,artoolkit/osg,artoolkit/osg,jtorresfabra/osg,marchelbling/osg,jtorresfabra/osg