tcpdump Bring change from upstream.

commit 772d6fbcf592209aa1ab1b61714e8ae72a5b1698
Author: Dmitrij Tejblum <tejblum@yandex-team.ru>
Date: Sun Jun 2 13:48:44 2013 +0400

Convert some versions of EXTRACT_{16,32,64}BITS() to inline functions.

It removes the vast majority of strict-aliasing warnings from GCC.