invoke.texi: Remove documentation for -fguiding-decls.

invoke.texi: Remove documentation for -fguiding-decls.

	* invoke.texi: Remove documentation for -fguiding-decls.

	Remove guiding declaration support.
	* cp/cp-tree.h (flag_dump_translation_unit): Make it const.
	(flag_guiding_decls): Remove.
	* call.c (build_user_type_conversion_1): Remove support for
	guiding decls.
	(build_new_function_call): Likewise.
	(build_new_op): Likewise.
	(build_new_method_call): Likewise.
	* decl.c (start_function): Likewise.
	* friend.c (is_friend): Likewise.
	(do_friend): Likewise.
	* decl2.c ((flag_dump_translation_unit): Make it const.
	(flag_guiding_decls): Remove.
	(unsupported_options): New variable
	(compare_options): New function.
	(lang_decode_option): Use them.

From-SVN: r34306