* linux-nat.c (PTRACE_O_TRACEVFORKDONE, PTRACE_O_TRACEEXIT): Define.

	* linux-nat.c (PTRACE_O_TRACEVFORKDONE, PTRACE_O_TRACEEXIT): Define.
	(PTRACE_EVENT_VFORKDONE, PTRACE_EVENT_EXIT): Define.
	(linux_parent_pid, linux_supports_tracevforkdone_flag): New variable.
	(linux_test_for_tracefork): Set linux_supports_tracevforkdone_flag.
	(linux_supports_tracevforkdone): New function.
	(linux_enable_event_reporting): Enable TRACEVFORK, TRACEEXEC, and
	TRACEVFORKDONE.
	(child_follow_fork): Handle vfork.
	(linux_handle_extended_wait): Likewise.  Also handle exec.
	(child_insert_vfork_catchpoint, child_insert_exec_catchpoint): Enable.
	* NEWS: Mention fork tracing.