anchor.diff:  assert libxcbshapeExtlib -> xorg.libxcb != null;
   assert gnutls != null -> openssl == null;
   assert openssl != null -> gnutls == null;
  -assert x11grabExtlib ->
  -  xorg.libX11 != null
  -  && xorg.libXv != null;
   
   let
     # Minimum/maximun/matching version
  
positive.code: #, vo-aacenc
  , vo-amrwbenc ? null
  , wavpack
  , x11grabExtlib ? false
  , x264
  , x265
  , xavs
  
negative.code:     "--${boolEn (SDL_2 != null)}-sdl"
      "--${boolEn (SDL_2 != null)}-sdl2"
      "--disable-securetransport"
      (deprfflag null "3.2" "--disable-x11grab")
      #"--${boolEn (xorg.libX11 != null && xorg.libXv != null)}-xlib"
      "--${boolEn (zlib != null)}-zlib"
      /*
  