invoke.texi (Warning Options): Add -Wmemset-elt-size.

invoke.texi (Warning Options): Add -Wmemset-elt-size.

	* doc/invoke.texi (Warning Options): Add -Wmemset-elt-size.
	(-Wmemset-elt-size): New item.
c-family/
	* c.opt (Wmemset-elt-size): New option.
	* c-common.c (warn_for_memset): New function.
	* c-common.h (warn_for_memset): Declare.
c/
	* c-parser.c (c_parser_postfix_expression_after_primary): Call
	warn_for_memset instead of warning directly here.
cp/
	* parser.c (cp_parser_postfix_expression): Call
	warn_for_memset instead of warning directly here.
testsuite/
	* c-c++-common/memset-array.c: New test.

From-SVN: r235475