We just failed to set the pixel format, so I don't think there's any reason to unset it here.
We can get there if setting pixel format succeeded but somehow wglMakeCurrent didn't, in which case we need to undo what we did.
Eh, okay. I'd prefer to clean it up in wined3d_context_gl_set_gl_context() then though; it's more idiomatic to have functions leave state alone on failure.
Before 2/4 this is just illegal, and after 2/4 the pixel format is per-DC, and we're releasing the DCs here, so this should have no effect?
But that's the point? `wglSetPixelFormatWINE(dc, 0)` is meant to be an explicit request to undo what was done in `wglSetPixelFormatWINE(dc, format)` and reset the DC internal pixel format and drawable, to avoid doing it `ReleaseDC` which has proven problematic in the past.
Wait, what? That's the first I've heard about it; what's the problem with doing it in ReleaseDC()? Or even, how can it be a problem to not reset the pixel format for a DC we're about to destroy?