Include pathnames are passed unchanged to ID3DInclude objects so e.g.
if a file is included as "path/file.h" the full pathname will have
mixed slashes.

I don't think the difference between d3d10 depth/stencil and rendertarget
views is large enough to justify a separate type. Unfortunately that does make
the name "wined3d_rendertarget_view" slightly awkward.