[boost] BOOST_HAS_NRVO not being set for VC++ 8.0

According to http://msdn.microsoft.com/visualc/default.aspx?pull=/library/en-us/dnvs05/ht..., VC++ 8.0 now support NRVO. Config info isn't reporting BOOST_HAS_NRVO as being set. Should this be changed? --Beman