use FindBin ();
use File::Spec::Functions qw/catfile/;
...
$p->parse_file(catfile($FindBin::Bin,qw/ .. lib Pod Simple Select.pm /));

##</code><code>##

use FindBin ();
use lib $FindBin::Bin;
...
my $script = catfile($FindBin::Bin, 'test_opts_usage.pl');