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