[boost] ICE with is_abstract on VC 7.0

When I compile anything that includes is_abstract.hpp I get a compiler ICE with VC 7.0 since is_abstract.hpp is included by type_traits.hpp it means that a large part of boost 1.31 release candidate 2 is now uncompilable on this platform. is_abstract was known to test the limits of many platforms. It is incredible to me that this could be dropped into "release candidate # 2" without having been part of the development tree for a reasonable amount of time. When can we expect 1.31 release candidate # 3? Robert Ramey