anchor.diff:  
     buildFlags = [ "VERSION=v${version}" "REVISION=${src.rev}" ];
   
  -  BUILDTAGS = [ ]
  -    ++ lib.optional (btrfs-progs == null) "no_btrfs";
  +  BUILDTAGS = lib.optionals (btrfs-progs == null) [ "no_btrfs" ];
   
     buildPhase = ''
  -    cd go/src/${goPackagePath}
       patchShebangs .
       make binaries man $buildFlags
     '';
  
positive.code: { lib
  , fetchFromGitHub
  , buildGoPackage
  , btrfs-progs
  , go-md2man
  , installShellFiles
  
negative.code: , nixosTests
  }:
  
  buildGoModule rec {
    pname = "containerd";
    version = "1.5.2";
  
    outputs = [ "out" "man" ];
  
    src = fetchFromGitHub {
      owner = "containerd";
      repo = "containerd";
      rev = "v${version}";
      sha256 = "sha256-RDLAmPBjDHCx9al+gstUTrvKc/L0vAm8IEd/mvX5Als=";
    };
  
    vendorSha256 = null;
  
    nativeBuildInputs = [ go-md2man installShellFiles util-linux ];
  
  