void *re_yyrealloc  (void * ptr, yy_size_t  size , yyscan_t yyscanner)
{
	struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
	(void)yyg;

	/* The cast to (char *) in the following accommodates both
	 * implementations that use char* generic pointers, and those
	 * that use void* generic pointers.  It works with the latter
	 * because both ANSI C and C++ allow castless assignment from
	 * any pointer type to void*, and deal with argument conversions
	 * as though doing an assignment.
	 */
	return (void *) realloc( (char *) ptr, size );
}

The product dereferences a pointer that it expects to be valid but is NULL.