* defs.h (quit_flag): Don't declare.

	* defs.h (quit_flag): Don't declare.
	(clear_quit_flag, check_quit_flag, set_quit_flag): Declare.
	(QUIT): Use new functions.
	* event-top.c (command_handler): Use clear_quit_flag.
	(handle_sigint): Use set_quit_flag.
	(async_request_quit): Use check_quit_flag.  Don't check
	immediate_quit.
	* exceptions.c (throw_exception): Use clear_quit_flag.
	* main.c (captured_main): Use clear_quit_flag.
	* python/python.c (clear_quit_flag, set_quit_flag)
	(check_quit_flag): New functions.
	* remote-sim.c (gdb_os_poll_quit): Use check_quit_flag,
	clear_quit_flag.
	* remote.c (remote_wait_as): Use check_quit_flag,
	clear_quit_flag.
	(remote_start_remote): Call QUIT.
	* symfile.c (load_progress): Use check_quit_flag.
	* top.c (command_loop): Use clear_quit_flag.
	(command_line_input): Call QUIT.
	* utils.c (quit_flag): Conditionally define.
	(clear_quit_flag, check_quit_flag, set_quit_flag): New
	functions.
	(prompt_for_continue): Call QUIT.  Use quit, not
	async_request_quit.
	* remote-mips.c (mips_expect_timeout): Call QUIT.
	* monitor.c (monitor_expect): Call QUIT.