Thank you dear monks! This was a good help!
My test script looks now like follows - and is working

#!/usr/bin/perl

use strict;
use warnings;

use Text::Autoformat;

$/ = '';

my $messy = <DATA>;

my $formatted = autoformat($messy, {all=>1});

print $formatted;

__DATA__

1. Analyze problem
3. Design algorithm
1. Code solution
5. Test
4. Ship
[download]

I would like nevertheless install a newer Perl with perlbrew

Could somebody help me with the linker problem? My Xcode is the newest version ...

marek

Have you looked at what Google provides as answer?

Google tells me that you need to use Xcode 7 and maybe add the appropriate library search directories.