anchor.diff:      # contains the string "perl", Configure would select $out/lib.
       # Miniperl needs -lm. perl needs -lrt.
       configureFlags =
  -      [ "-de"
  -        "-Dcc=cc"
  +      (if crossCompiling
  +       then [ "-Dlibpth=\"\"" "-Dglibpth=\"\"" ]
  +       else [ "-de" "-Dcc=cc" ])
  +      ++ [
           "-Uinstallusrbinperl"
           "-Dinstallstyle=lib/perl5"
           "-Duseshrplib"
  
positive.code: { lib, stdenv, fetchurlBoot, enableThreading ? stdenv ? glibc }:
  
  with lib;
  
  
negative.code:       pwd="$(type -P pwd)"
        substituteInPlace dist/PathTools/Cwd.pm \
          --replace "/bin/pwd" "$pwd"
      '' + stdenv.lib.optionalString crossCompiling ''
        substituteInPlace cnf/configure_tool.sh --replace "cc -E -P" "cc -E"
      '';
  
      # Build a thread-safe Perl with a dynamic libperls.o.  We need the
  