cmake HELLOIMGUI_HAS_DIRECTX12 examples

pthom/hello_imgui CMakeLists.txt :94 

option(HELLOIMGUI_HAS_DIRECTX12 "Use DirectX12 as a rendering backend" OFF)

pthom/hello_imgui hello_imgui_cmake/hello_imgui_build_lib.cmake :112 

message(WARNING "
        HELLOIMGUI_USE_SDL_DIRECTX12 is deprecated,
        use HELLOIMGUI_USE_SDL2 + HELLOIMGUI_HAS_DIRECTX12 instead")

pthom/hello_imgui hello_imgui_cmake/hello_imgui_build_lib.cmake :932 

target_compile_definitions(${HELLOIMGUI_TARGET} PUBLIC HELLOIMGUI_HAS_DIRECTX12)