Also avoid dependency on winternl.h.

widl: Consolidate top-level parameter conformance/variance expression writing into a separate function.

Descend through as many pointer types as necessary to find the
fundamental type and determine whether it needs a top-level parameter
conformance/variance expression to be written.

Add support for writing top-level parameter conformance/variance
expressions for non-encapsulated unions.

This gets rid of depth_copy_state in the device, and instead tracks
the most up to date location per-surface. This makes things a lot
easier to follow, and allows us to make a copy when switching depth
stencils in SetDepthStencilSurface().

This makes the depth copy independent of the currently attached render
targets. This is important for the next patch because it might do a
depth copy when the render targets aren't in a valid configuration
(SetDepthStencilSurface()).

wined3d: Make sure the FBO doesn't have any depth attachments in color_fill_fbo() and stretch_rect_fbo().

Currently this is already true, but the next patch will break that assumption.