anchor.diff:        }
       else
         fetchurl {
  -        url = "https://bitbucket.org/multicoreware/x265/downloads/"
  -          + "x265_${source.version}.tar.gz";
  +        urls = [
  +          ("https://bitbucket.org/multicoreware/x265/downloads/"
  +            + "x265_${source.version}.tar.gz")
  +          ("mirror://videolan/x265/x265_${source.version}.tar.gz")
  +        ];
           inherit (source) multihash sha256;
         };
   
  
positive.code:     rm -v $out/lib/libx265.a
    '';
  
    meta = with lib; {
      description = "Library for encoding h.265/HEVC video streams";
      homepage = http://x265.org;
  
negative.code:   sources = {
      "stable" = {
        version = "3.0";
        md5confirm = "8ff1780246bb7ac8506239f6129c04ec";
        multihash = "QmTRoGtatifcPPHjL22njyYSn381wb6wJsrrDzZXtVMjm7";
        sha256 = "c5b9fc260cabbc4a81561a448f4ce9cad7218272b4011feabc3a6b751b2f0662";
      };
      "head" = {
  