While comparing regression tests results for Boost.Build V1 and V2, I noted that some date_time tests fail, and traced this to the fact that V2 does not define USE_DATA_TIME_PRE_1_33_FACET_IO while compiling the tests. So, I have a couple of questions: 1. What does the macro do? I could not find anything in the docs. 2. For V2, I have as much as three choices: - Add this define to the same sets of tests and in V1 Jamfile - Add this define to "project requirements" for the date_time/test Jamfile.v2, so it will be applied to all targets - Add this define to "usage requirements" for the date_time library, so that any executable files linking to date_time will get this define set. Which option is the best? Thanks, Volodya