CXXD_UNORDERED_SET_USE_BOOST — Override macro for Boost unordered set implementation.
// In header: <boost/cxx_dual/impl/unordered_set.hpp> CXXD_UNORDERED_SET_USE_BOOST
The object-like macro, when defined to nothing prior to including this header file, forces the dual library choice of the Boost unordered set implementation.
