The extracted directory contains 1246 Files (8.75 MB), and it looks like it contains bind, function, iterator, mpl, preprocessor, regex, thread, type_traits, utility, smart_ptr libraries from boost. (boost/mpl contains 649 files, boost/preprocessor contains 149 files)
Although I used make files to build (VC80), when building regex, it didn't require the thread library. I wonder whether it is really necessary.
It's used as a fallback when it can't otherwise identify the threading model, and I suspect that Boost.Thread is responsible for pulling in bind and function (since I don't use them).
I wonder whether similar tricks are available for regex as well.
You could comment out the thread lib includes in boost/regex/pending/static_mutex.hpp and see if that helps. John.