anchor.diff:    libc = if stdenv.cc.libc or null != null then stdenv.cc.libc else "/usr";
     libcInc = lib.getDev libc;
     libcLib = lib.getLib libc;
  -  common = { version, sha256 }: stdenv.mkDerivation rec {
  +  crossCompiling = stdenv.buildPlatform != stdenv.hostPlatform;
  +  common = { version, sha256 }: stdenv.mkDerivation (rec {
       name = "perl-${version}";
   
       src = fetchurlBoot {
  
positive.code:       ++ optional stdenv.isSunOS "-Dcc=gcc"
        ++ optional enableThreading "-Dusethreads";
  
      configureScript = "${stdenv.shell} ./Configure";
  
      dontAddPrefix = true;
  
      enableParallelBuilding = true;
  
      preConfigure =
        ''
          configureFlags="$configureFlags -Dprefix=$out -Dman1dir=$out/share/man/man1 -Dman3dir=$out/share/man/man3"
        '' + optionalString (stdenv.isArm || stdenv.isMips) ''
          configureFlagsArray=(-Dldflags="-lm -lrt")
  
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
  