PR c/22476
	* c-common.c (check_function_arguments): Call
	'check_function_format' if either -Wformat or
	-Wmissing-format-attribute are specified.
	* c-format.c (check_function_format): Check -Wformat before
	calling 'check_format_info'.
	* c-opts.c (c_common_post_options): Don't warn for
	-Wmissing-format-attribute without -Wformat.
	* c-typeck.c (convert_for_assignment): Detect additional cases for
	-Wmissing-format-attribute.
	* doc/invoke.texi (-Wmissing-format-attribute): Document new
	behavior.

testsuite:
	* gcc.dg/format/miss-1.c, gcc.dg/format/miss-2.c: Don't
	specify -Wformat for these tests.
	* gcc.dg/format/miss-3.c, gcc.dg/format/miss-4.c,
	gcc.dg/format/miss-5.c, gcc.dg/format/miss-6.c: New.
	* gcc.dg/format/opt-6.c: Delete.

From-SVN: r102155