anchor.diff:        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)'"
  -    '';
  +  preBuild = if (stdenv.gcc.nativeTools) then preBuildNative else preBuildNoNative;
   
     setupHook = ./setup-hook.sh;
   }
  
positive.code: {stdenv, fetchurl}:
  
  stdenv.mkDerivation {
    name = "perl-5.10.0";
  
  
negative.code:   # "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 ""}
    '';
  
  