anchor.diff:  
   stdenv.mkDerivation rec {
     name = "libvpx-${version}";
  -  version = "1.4.0";
  +  version = "1.5.0";
   
     src = fetchFromGitHub {
       owner = "webmproject";
       repo = "libvpx";
       rev = "v${version}";
  -    sha256 = "1y8cf2q5ij8z8ab5j36m18rbs62aah6sw6shzbs3jr70ja0z6n8s";
  +    sha256 = "19ill4c7dak5f8m4pdbas87zknw3a34sca8a4i952q0l0jnif0np";
     };
   
     patchPhase = ''patchShebangs .'';
  
positive.code:     "--as=yasm"
      # Limit default decoder max to WHXGA
      (if sizeLimitSupport then "--size-limit=5120x3200" else null)
      (enableFeature fastUnalignedSupport "fast-unaligned")
      "--disable-codec-srcs"
      (enableFeature debugLibsSupport "debug-libs")
      (enableFeature isMips "dequant-tokens")
  
negative.code:     (enableFeature (postprocSupport && (vp9DecoderSupport || vp9EncoderSupport)) "vp9-postproc")
      (enableFeature multithreadSupport "multithread")
      (enableFeature internalStatsSupport "internal-stats")
      #(enableFeature memTrackerSupport "mem-tracker")
      (enableFeature spatialResamplingSupport "spatial-resampling")
      (enableFeature realtimeOnlySupport "realtime-only")
      (enableFeature ontheflyBitpackingSupport "onthefly-bitpacking")
  