* event-loop.c (struct callback_event): New struct.

	(callback_list): New global.
	(append_callback_event, delete_callback_event): New functions.
	(process_callback): New function.
	(start_event_loop): Call it.
	* remote-utils.c (NOT_SCHEDULED): Define.
	(readchar_buf, readchar_bufcnt, readchar_bufp): New static globals,
	moved out of readchar.
	(readchar): Rewrite.  Call reschedule before returning.
	(reset_readchar): New function.
	(remote_close): Call it.
	(process_remaining, reschedule): New functions.
	* server.h (callback_handler_func): New typedef.
	(append_callback_event, delete_callback_event): Declare.