perl says defined(@array) is deprecated.

The relation between src and dst pitches is not correct if the source
pitch is padded to match pitch alignment requirements.

winex11: Don't trace a garbage value or read past end of caller's array in X11DRV_wglChoosePixelFormatARB().

We always have a swapchain here, even if there are no back buffers.

Depending on the location flags, the buffer or heap_memory should be
used.