CXXD_WEAK_PTR_HEADER — The weak_ptr header file name.
// In header: <boost/cxx_dual/impl/weak_ptr.hpp> CXXD_WEAK_PTR_HEADER
The object-like macro expands to the include header file designation for the weak_ptr header file. The macro is used with the syntax: #include CXXD_WEAK_PTR_HEADER
