2001-06-12 Michael Snyder <msnyder@redhat.com>

2001-06-12  Michael Snyder  <msnyder@redhat.com>

	* lin-lwp.c: Prevent thread starvation by using a monte carlo
	method to choose which of several event threads to handle next.

	(stop_wait_callback): Defer pushback of breakpoint events until
	later; add SIGTRAP events to the queue of unhandled events.
	Keep calling waitpid until SIGSTOP retrieved.  If more than one
	non-SIGSTOP event is retrieved, push them back onto the process
	queue using kill.
	(count_events_callback, select_singlestep_lwp_callback,
	select_event_lwp_callback, cancel_breakpoints_callback,
	select_event_lwp): New functions.  Implement monte carlo method
	for selecting which of several SIGTRAP threads to handle next.
	Push back the breakpoint event for all threads other than the
	selected one.
	(lin_lwp_wait): Call select_event_lwp to decide which of several
	sigtrapped lwps to handle next.
	(resume_callback): Disable code that attempts to handle
	step_resume breakpoints.  Let core gdb handle this.