* remote-sim.c: Include gdbthread.h.

	* remote-sim.c: Include gdbthread.h.
	(remote_sim_ptid): New global.
	(gdbsim_create_inferior): Silently add the main task to GDB's
	thread list.
	(gdbsim_close, gdbsim_mourn_inferior): Silently delete the main
	task from GDB's thread list.
	(gdbsim_resume): Adjust to use remote_sim_ptid.
	(gdbsim_thread_alive, gdbsim_pid_to_str): New.
	(init_gdbsim_ops): Register gdbsim_thread_alive and
	gdbsim_pid_to_str.
	(_initialize_remote_sim): Initialize remote_sim_ptid.
	* Makefile.in (remote-sim.o): Depend on $(gdbthread_h).