The attached patch fixes all warnings in tdep-i386.c resulting from
enabling shadow warnings in gcc. As this is my first contribution to
GDB, I decided to keep it short to a single file to obtain feedback.

2012-08-05  Goncalo Gomes <goncalo@promisc.org>

        * Refactor tdep-i386.c to fix all -Wshadow warnings

Goncalo