Added ARCH64 def for 64 bit builds
Added ARCH64 def for 64 bit builds


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