This allows proper support of float depth buffers when rendering to onscreen surfaces.

This allows the swapchain to know what depth format its window contexts have to see if the
requested depth format is compatible or a FBO fallback is needed, and it will be needed to
set the onscreen format to the requested auto depth stencil format instead of the
let's-hope-it-fits D24_UNORM_S8_UINT format.

winedbg: When filling an imagehlp frame information, also do the stack field, it's used on x86-64 platforms.