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.
When trying to do a small optimization in 8a0f5ea, I failed to
take into account that WeakFlush and FlushOne update m_query_count.
Only D3D11 and OGL had this problem, not D3D12 and Vulkan.
