Fix Doxygen conf to support __UNUSED__
Fix Doxygen conf to support __UNUSED__

SVN revision: 54434

rvandegrift/elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary