New review comment by unspecd on void-packages repository

https://github.com/void-linux/void-packages/pull/35049#discussion_r785865792

Comment:
No, they use SDL_Overlay is no longer available in SDL2: 
```console
$ git clone https://github.com/gnuradio/gnuradio
$ cd gnuradio && grep -Rhow 'SDL_[A-Z][a-z][a-zA-Z]*' gr-video-sdl/lib/ | sort | uniq
SDL_CreateYUVOverlay
SDL_Delay
SDL_DisplayYUVOverlay
SDL_Flip
SDL_FreeYUVOverlay
SDL_GetError
SDL_GetTicks
SDL_Init
SDL_LockYUVOverlay
SDL_Overlay
SDL_Quit
SDL_Rect
SDL_SetVideoMode
SDL_Surface
SDL_UnlockYUVOverlay
```