anchor.diff:      "--${boolEn (openal != null)}-openal"
       #"--${boolEn (opencl != null)}-opencl"
       /**/"--disable-opencl"
  -    # OpenGL requires libX11 for GLX
  -    "--${boolEn (mesa_noglu != null && xorg.libX11 != null)}-opengl"
  +    "--${boolEn (opengl-dummy != null && opengl-dummy.glx)}-opengl"
       "--${boolEn (openssl != null)}-openssl"
       "--disable-schannel"  # windows
       "--${boolEn (SDL_2 != null)}-sdl"
  
positive.code:     libvorbis
      libvpx
      libwebp
      mesa_noglu
      mfx-dispatcher
      nvidia-cuda-toolkit
      nvidia-drivers
      openal
      openh264
      openjpeg
      opus
  
negative.code: #, opencl
  #, opencore-amr
  , opencv
  , opengl-dummy
  , openh264
  , openjpeg
  , openssl
  