This undocumented "private" class was used for various windows UxTheme
functions which are available since WinXP. As wxWidgets 3.1 is XP+ it
does not make sense anymore to load the theme functions dynamically.
Explicitly include $(BCCDIR)/include/windows/sdk directory in the resource
compiler options, as it needs it to find windows.h.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77993 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775