Official Dear ImGui backend for Direct3D 11, unmodified:
https://github.com/ocornut/imgui, tag v1.92.9b (same version as tools/port/nvnvk/third_party/imgui),
files backends/imgui_impl_dx11.cpp and backends/imgui_impl_dx11.h.
MIT license, same as Dear ImGui (tools/port/nvnvk/third_party/imgui/LICENSE.txt).
