new UDF arguments interface (WL#1017) (SCRUM)

include/mysql_com.h

@@ -278,6 +278,8 @@ typedef struct st_udf_args
   char **args;				/* Pointer to argument */
   unsigned long *lengths;		/* Length of string arguments */
   char *maybe_null;			/* Set to 1 for all maybe_null args */
+  char **attributes;                    /* Pointer to attribute name */
+  unsigned long *attribute_lengths;     /* Length of attribute arguments */
 } UDF_ARGS;
 
   /* This holds information about the result */