Upgrade to threads::shared 1.31

Upgrade to threads::shared 1.31

Attached patch changes t/stress.t such that it more robustly handles
thread creation failures due to 'no more processes', 'out of memory',
etc..  Such failures are not indicative of problems with the
'threads::shared' module.

From 2440c97ff633f0a33bf1ca0cceecfd4448cd6167 Mon Sep 17 00:00:00 2001
From: Jerry D. Hedden <jdhedden@cpan.org>
Date: Mon, 10 Aug 2009 15:22:54 -0400
Subject: [PATCH] Upgrade to threads::shared 1.31

Signed-off-by: H.Merijn Brand <h.m.brand@xs4all.nl>