Fixing compiler warnings:
 - Building Breakpad in Xcode with arm64 architecture.
 - iOS
Patches provided by: Ian Hickson and Greg Vance.

R=mark@chromium.org

Review URL: https://breakpad.appspot.com/1184003

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1286 4c0a9323-5329-0410-9bdc-e9ce6186880e