* Add a "fault_callback" to the thread structure which is called when a
unhandled page fault happens in user space. A SIGSEGV will only be sent
if the callback returns "true".
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25609 a95241bf-73f2-0310-859d-f6bbb57e9c96