CMake: Enable WASAPI on WinRT

WASAPI backend on WinRT was implemented with 2.0.8
https://github.com/libsdl-org/SDL/commit/351d6d478443fe8a1ede1e993712f07cb369d483
but CMake source here was written for 2.0.7 in vcpkg
https://github.com/microsoft/vcpkg/commit/e6c65b93b125cf0be13254cf2f5a9d27cb009707

CMakeLists.txt

@@ -1505,9 +1505,12 @@ elseif(WINDOWS)
       set(SOURCE_FILES ${SOURCE_FILES} ${DSOUND_AUDIO_SOURCES})
     endif()
 
-    if(WASAPI AND HAVE_AUDIOCLIENT_H AND HAVE_MMDEVICEAPI_H AND NOT WINDOWS_STORE)
+    if(WASAPI AND HAVE_AUDIOCLIENT_H AND HAVE_MMDEVICEAPI_H)
       set(SDL_AUDIO_DRIVER_WASAPI 1)
       file(GLOB WASAPI_AUDIO_SOURCES ${SDL2_SOURCE_DIR}/src/audio/wasapi/*.c)
+      if(WINDOWS_STORE)
+        list(APPEND WASAPI_AUDIO_SOURCES ${SDL2_SOURCE_DIR}/src/audio/wasapi/SDL_wasapi_winrt.cpp)
+      endif()
       set(SOURCE_FILES ${SOURCE_FILES} ${WASAPI_AUDIO_SOURCES})
     endif()
   endif()