Commit 02fe9f5bdf introduced linking the
Windows build of the demos with d3d12 and dxgi, while also still linking
to libvkd3d-utils.la. That happens to more or less work on Wine; we get
vkd3d-utils' D3D12CreateDevice(), and Wine's
IDXGIFactory2_CreateSwapChainForHwnd(), but because Wine's
implementation of d3d12 swapchains uses vkd3d, we're able to use the
resulting swapchain buffers even though the instance of vkd3d used by
Wine may not be the same instance of vkd3d used by the demos. Perhaps
unsurprisingly, things don't go nearly as well on Windows.
We could of course stop linking the demos to vkd3d-utils on Windows, but
that's not that interesting; we're trying to show what vkd3d can do
here, not what d3d12 can do.
Much like we did for demo_xcb.h, demo_win32.h now just has the bits for
creating windows and handling events, while demo_d3d12.h has the d3d12
and dxgi bits.
