anchor.diff:      (enableFeature ontheflyBitpackingSupport "onthefly-bitpacking")
       (enableFeature errorConcealmentSupport "error-concealment")
       # Shared libraries are only supported on ELF platforms
  -    (if isDarwin || isCygwin then
  -       "--enable-static --disable-shared"
  -     else
  -       "--disable-static --enable-shared")
  +    "--disable-static --enable-shared"
       (enableFeature smallSupport "small")
       (enableFeature postprocVisualizerSupport "postproc-visualizer")
       (enableFeature unitTestsSupport "unit-tests")
  
positive.code:     (enableFeature gprofSupport "gprof")
      (enableFeature gcovSupport "gcov")
      # Required to build shared libraries
      (enableFeature (!isCygwin) "pic")
      (enableFeature (isi686 || isx86_64) "use-x86inc")
      (enableFeature optimizationsSupport "optimizations")
      (enableFeature runtimeCpuDetectSupport "runtime-cpu-detect")
  
negative.code: assert postprocVisualizerSupport -> postprocSupport;
  assert unitTestsSupport -> curl != null && coreutils != null;
  assert vp9HighbitdepthSupport -> (vp9DecoderSupport || vp9EncoderSupport);
  
  stdenv.mkDerivation rec {
    name = "libvpx-${version}";
  