anchor.diff:    # "installstyle" option to ensure that modules are put under
     # $out/lib/perl5 - this is the general default, but because $out
     # contains the string "perl", Configure would select $out/lib.
  +  # Miniperl needs -lm. perl needs -lrt.
     configureFlags = ''
       -de -Dcc=gcc -Uinstallusrbinperl -Dinstallstyle=lib/perl5 -Duseshrplib
  +    -Dldflags='-lm -lrt'
       ${if stdenv ? glibc then "-Dusethreads" else ""}
     '';
   
  
positive.code:       fi
      '';
  
    preBuild =
      ''
        # Make Cwd work on NixOS (where we don't have a /bin/pwd).
        substituteInPlace lib/Cwd.pm --replace "'/bin/pwd'" "'$(type -tP pwd)'"
      '';
  
    setupHook = ./setup-hook.sh;
  }
  
negative.code: {stdenv, fetchurl}:
  
  let
    preBuildNoNative = ''
        # Make Cwd work on NixOS (where we don't have a /bin/pwd).
        substituteInPlace lib/Cwd.pm --replace "'/bin/pwd'" "'$(type -tP pwd)'"
      '';
    preBuildNative = "";
  in
  stdenv.mkDerivation {
    name = "perl-5.10.0";
  
  