* macfns.c: Include sys/param.h.

* macfns.c: Include sys/param.h.
	[TARGET_API_MAC_CARBON] (mac_nav_event_callback): New declaration
	and function.
	[TARGET_API_MAC_CARBON] (Fx_file_dialog): Use MAXPATHLEN for size
	of filename string.  Set event callback function when creating
	dialog boxes.  Add code conversions for filenames.  Don't dispose
	apple event descriptor record if failed to create it.
* macterm.c: Include sys/param.h.
	[USE_CARBON_EVENTS] (mac_handle_window_event): Add handler for
	kEventWindowUpdate.
	(install_window_handler) [USE_CARBON_EVENTS]: Register it.
	(do_ae_open_documents) [TARGET_API_MAC_CARBON]: Get FSRef instead
	of FSSpec from apple event descriptor record.
	(do_ae_open_documents) [TARGET_API_MAC_CARBON]: Use MAXPATHLEN for
	size of filename string.
	[TARGET_API_MAC_CARBON] (mac_do_receive_drag): Likewise.
	[TARGET_API_MAC_CARBON] (mac_do_receive_drag): Return error when a
	file dialog is in action.
	[TARGET_API_MAC_CARBON] (mac_do_track_drag): Likewise.  Reject
	only when there are no filename items.  Set background color
	before (un)highlighting the window below the dragged items.
	(XTread_socket) [!USE_CARBON_EVENTS]: Don't call do_window_update.