* c-common.c (enum format_type): Add strfmon_format_type.
	(decl_attributes): Handle format attributes strfmon and
	__strfmon__.
	(FMT_FLAG_USE_DOLLAR, FMT_FLAG_ZERO_WIDTH_BAD,
	FMT_FLAG_EMPTY_PREC_OK): Define.
	(format_char_info): Update comment for flag_chars.
	(format_flag_spec): Add skip_next_char.
	(format_kind_info): Add left_precision_char.
	(printf_flag_specs, scanf_flag_specs, strftime_flag_specs,
	format_types): Update for these new structure members and flags.
	(time_char_table): Make const.
	(strfmon_length_specs, strfmon_flag_specs, strfmon_flag_pairs,
	monetary_char_table): New.
	(format_types): Add details of strfmon formats.
	(init_function_format_info): Create default attribute for strfmon.
	(check_format_info_main): Check the new flags.  Handle
	skip_next_char and left precision.
	* toplev.c (documented_lang_options): Update description of
	-Wformat.
	* extend.texi: Document strfmon format attributes.  Document
	attribute forms such as __printf__.  Clarify format_arg attribute
	documentation.
	* invoke.texi (-Wformat): Update for strfmon formats.

testsuite:
	* gcc.dg/format-strfmon-1.c: New test.

From-SVN: r38512