anchor.diff:      "--${boolEn (libvpx != null)}-libvpx"
       "--${boolEn (wavpack != null)}-libwavpack"
       "--${boolEn (libwebp != null)}-libwebp"
  -    # FIXME: remove hack for 3.4.2+
  -    (
  -      if compareVersions "3.4.2" source.version != 1 then
  -        "--${boolEn (x264 != null)}-libx264"
  -      else
  -        "--disable-libx264"
  -    )
  +    "--${boolEn (x264 != null)}-libx264"
       "--${boolEn (x265 != null)}-libx265"
       "--${boolEn (xavs != null)}-libxavs"
       #"--${boolEn (libxcb != null)}-libxcb"
  
positive.code: 
    sources = {
      "3.4" = {
        version = "3.4.1";
        multihash = "QmbxvBJpsNPSRDR8HyQDAzgSoqj8raaR4FewSXPAL8TMww";
        sha256 = "5a77278a63741efa74e26bf197b9bb09ac6381b9757391b922407210f0f991c0";
      };
      "9.9" = {  # Git
        fetchzipversion = 5;
  
negative.code:   };
    source = sources."${channel}";
  in
  
  /*
   *  Licensing dependencies
  