anchor.diff:        "-Dlocincpth=${libc}/include"
         "-Dloclibpth=${libc}/lib"
       ]
  -    ++ stdenv.lib.optional (stdenv ? glibc) "-Dusethreads";
  +    ++ optional (stdenv ? glibc) "-Dusethreads";
   
     configureScript = "${stdenv.shell} ./Configure";
   
  
positive.code:     [ # Do not look in /usr etc. for dependencies.
        ./no-sys-dirs.patch
      ]
      ++ stdenv.lib.optional stdenv.isSunOS  ./ld-shared.patch
      ++ stdenv.lib.optional stdenv.isDarwin ./no-libutil.patch;
  
    # Build a thread-safe Perl with a dynamic libperls.o.  We need the
    # "installstyle" option to ensure that modules are put under
  
negative.code:     ''
        configureFlags="$configureFlags -Dprefix=$out -Dman1dir=$out/share/man/man1 -Dman3dir=$out/share/man/man3"
  
        ${optionalString stdenv.isArm ''
          configureFlagsArray=(-Dldflags="-lm -lrt")
        ''}
      '';
  
    preBuild = optionalString (!(stdenv ? gcc && stdenv.gcc.nativeTools))
      ''
        # Make Cwd work on NixOS (where we don't have a /bin/pwd).
        substituteInPlace dist/Cwd/Cwd.pm --replace "'/bin/pwd'" "'$(type -tP pwd)'"
  