Is right recursive C grammar necessary?

[Rich Chomiczewski]

The ANSI C yacc parser written by Jeff Lee contains right recursive rules.
For example:

	declaration_specifiers
		: storage_class_specifier
	 	| storage_class_specifier declaration_specifiers
			etc.
		;

Is this right recursive grammar required by the ANSI C committee?
Can the above rule be written left recursive and still conform
to the ANSI C standard?
___
Rich (erc3ba!rsc)