[boost] [chrono] stopwatches tests failing

Hi, currently all the stopwatches tests are failing with fatal error C1083: Cannot open include file: 'boost/chrono/stopwatches/stopwatch.hpp': No such file or directory (on MSVC). Apparently no symlink is created for the newly moved stopwatches subdirectory. Unfortunately I have no idea how to tell Boost.Build to do that.