[boost] [1.40.0] [threads] Unmerged threads changesets

There are at least nine Boost.Threads changesets in trunk that have not been merged into the release branch. They date back to February. There are several multiple-platform trunk test failures that seem related to one or more of these changesets. I pinged Anthony yesterday about one of the changesets, but have had no reply. Given the above, plus the fact that 1.40.0 is really late already, I'm going to go ahead with the release without these changesets. --Beman