SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
It appears that some older drivers do not support
CreateSwapChainForHwnd, resulting in DXGI_ERROR_INVALID_CALL. For these
cases, fall back to the base CreateSwapChain() from DXGI 1.0.
In theory this should also let us run on Win7 without the platform
update, but in reality we require the newer shader compiler so this
probably won't work regardless. Also any hardware of this vintage is
unlikely to run Dolphin well.
