anchor.diff:    libcLib = lib.getLib libc;
     crossCompiling = stdenv.buildPlatform != stdenv.hostPlatform;
   
  -  common = { self, buildPerl, version, sha256 }: stdenv.mkDerivation (rec {
  +  common = { perl, buildPerl, version, sha256 }: stdenv.mkDerivation (rec {
       inherit version;
   
       name = "perl-${version}";
  
positive.code: 
    # the latest Devel version
    perldevel = common {
      self = perldevel;
      buildPerl = buildPackages.perldevel;
      version = "5.29.9";
      sha256 = "017x3nghyc5m8q1yqnrdma96b3d5rlfx87vv5mi64jq0r8k6zppm";
  
negative.code:     # TODO merge setup hooks
      setupHook = ./setup-hook-cross.sh;
    });
  in {
    # the latest Maint version
    perl528 = common {
      perl = pkgs.perl528;
      buildPerl = buildPackages.perl528;
      version = "5.28.2";
      sha256 = "1iynpsxdym4h76kgndmn3ykvwxhqz444xvaz8z2irsxkvmnlb5da";
  