Patches from Jerry Blakely <gerry_blakley@wellfleet.com>:

	Patches from Jerry Blakely <gerry_blakley@wellfleet.com>:
	* as.c (listing_filename): New static variable.
	(show_usage): Mention -a=file.
	(parse_args): Support = option of -a to set name of listing file.
	(main): Pass listing_filename to listing_print.
	* listing.c (list_file): New static variable.
	(various): Replace printf with fprintf to list_file.
	(listing_print): If name argument is not NULL, open it as
	list_file.
	* doc/as.texinfo, doc/as.1: Document -a=file.
PR 6354.