I'm trying to fix bcp to work again and adding tests for it (boostorg/bcp@1025e7e), and I'm using program_options because it's the only library exercising the boost-lib rule from Jamroot, which was one of the things that were broken.

bcp --namespace=foo renames the libraries from boost_bar to foo_bar, but it doesn't touch test/Jamfile, which still wanted to link to boost_program_options. Changing it to refer to /boost//program_options instead fixes it.

The manual <define>BOOST_PROGRAM_OPTIONS_DYN_LINK=1 was unnecessary, because it was supplied by boost-lib, and it masked the fact that boost-lib was erroneously changed by bcp to define FOO_PROGRAM_OPTIONS_DYN_LINK instead.