[boost] [typeof] patch for typeof.hpp

boost/typeof/typeof.hpp has conditionalization for the compilers that do not support typeof extension. For such compilers, defining BOOST_TYPEOF_NATIVE macro results in a "native typeof is not supported" error. The condition does not include aCC and cxx compilers. Since on the platforms not supporting typeof extension "_native" subset of typeof library tests is marked known failure, the test system does not flag this omission: the "_native" tests fail to compile anyway. Attached patch fixes this problem. Tested on Tru64 and HP-UX. Ok to commit to HEAD? Thanks, Boris