Using __stdcall before the return type results in a warning with VC6 and an
error with VC9, place it after the return type.
Also use wxSTDCALL instead of just __stdcall for potentially better
compatibility with other compilers.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62800 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775