Okay, so I have made a bit of progress. After building Boost.Asio with:
b2 --with-system --with-thread --with-date_time --with-regex --with-serialization stage
, and building Boost.Chrono with (replacing bjam with b2):
bjam libs/chrono/build
The code is now compiling with the following g++ command:

g++ -v -Wall -L ${BOOST_ROOT}/stage/lib -L ${BOOST_ROOT}/bin.v2/libs/chrono/build/clang-darwin-11.0/debug/threading-multi/visibility-hidden -lboost_chrono -lboost_date_time -lboost_system -I. -I${BOOST_ROOT} -o main main.cpp


However, when I go to run main, the program crashes with the following message: 

dyld: Library not loaded: @rpath/libboost_chrono.dylib

  Referenced from: /Users/ajm/Projects/boost-threads/ex1/./main

  Reason: image not found

Abort trap: 6


I suspect that there is something wrong with the Boost.Chrono dynamic library file that was built (probably because of how I built it), but I am not sure what it would be. Any suggestions?

Thanks,

Andrew J. E. McFarlane