[boost] [functional/hash] Failing link_ext_test on Windows both trunk and release

link_ext_test has a link failure on Windows both trunk and release. See http://beta.boost.org/development/tests/release/developer/functional-hash.ht... We need to clear this ASAP. --Beman PS: The error is an unresolved external to "test_main" in Boost.Test, so this may be a Jamfile problem rather than a problem with the library's actual code.