* c-common.c (check_format_info): Properly save the argument

	* c-common.c (check_format_info): Properly save the argument
	number and parameter for $ operand number formats in case width
	and precision arguments are also used.  Allow printf width and
	precision arguments to have operand numbers even if none was
	specified for the main format, since this is OK for %*.*m.  Only
	object to missing $ operand number if the format used requires an
	argument.

testsuite:
	* gcc.dg/format-ext-1.c: Add tests for mixing %m with $ formats.
	* gcc.dg/format-xopen-1.c: Fix error in one $ format test.  Add
	more $ format tests.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@36493 138bc75d-0d04-0410-961f-82ee72b054a4