PR go/64595
	* go-lang.c (go_langhook_init_options_struct): Set default
	debug_info_level.
	(go_langhook_post_options): If debug_info_level is still the
	default, make sure write_symbols is set.
	* gccgo.texi (Invoking gccgo): Document that -g1 is the default.

From-SVN: r220064