Unfortunately, jam fails to build the test app too.

The errors reported when trying to link 'test_thread' and are from thread.o: undefined reference to nanosleep undefined reference to sched_yield

...

Hopefully others will have more information for you.

Lets hope.

Adding -lrt -lpthread -lposix4 to the LINKFLAGS for <threading>multi makes an app that links and runs passing the tests. - Dale.