[boost] [functional/hash] Reason for failure of hash_float_test on Tru64/CXX

As can be seen at http://tinyurl.com/9lded there is a failure for a very specific test of the hash function on Tru64/cxx65-042. I finally took the time to track this down and it turned out to be due to a bogus return value of std::numeric_limits<long double>::denorm_min(). The good news is that it's fixed in the latest compiler release. But should the failure be marked as expected for older versions of the compiler, or should a workaround be added to the test itself? Any preferences? Markus