anchor.diff:  let
     inherit (builtins)
       compareVersions;
  -  inherit (stdenv.lib)
  +  inherit (lib)
       boolEn
       optional
       optionals
  
positive.code: { stdenv
  , fetchFromGitHub
  , fetchurl
  , perl
  , texinfo
  , yasm
  
negative.code: , mfx-dispatcher
  , mmal ? null
  , netcdf ? null
  , nvenc ? false
  , nvidia-cuda-toolkit
  , nvidia-drivers
  , openal
  