Add SIGABRT handler for mac and iOS.

 SIGABRT were not handled while in process. This change add a signal handler to
handle this.
Review URL: https://breakpad.appspot.com/360001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@933 4c0a9323-5329-0410-9bdc-e9ce6186880e
3 files changed