* c-common.c (init_dollar_format_checking,
	maybe_read_dollar_number, finish_dollar_format_checking): New
	functions.
	(dollar_arguments_used, dollar_arguments_count,
	dollar_first_arg_num, dollar_max_arg_used, dollar_format_warned):
	New variables.
	(check_format_info): Support $ formats for scanf and printf width
	and precision.  Always increment format_chars to advance past the
	'*' of precision, not just when the format parameters are
	available to check.

testsuite:
	* gcc.dg/c90-printf-3.c, gcc.dg/c90-scanf-2.c,
	gcc.dg/c90-scanf-3.c, gcc.dg/c90-scanf-4.c,
	gcc.dg/c90-strftime-1.c, gcc.dg/c99-printf-3.c,
	gcc.dg/c99-scanf-1.c, gcc.dg/c99-scanf-2.c, gcc.dg/c99-scanf-3.c,
	gcc.dg/format-xopen-1.c: New tests.

From-SVN: r35856