libstdc++ (which is used by Clang) defines numeric_limits<> as a struct and Clang issues a warning about our specialization that uses 'class'. As libstdc++ developers have no intention of fixing this, silence the Clang warning by using 'struct' for it. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68472 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775