enclose RHASH_XXX macros by parenthesis.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13310 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

include/ruby/ruby.h

@@ -483,8 +483,8 @@ struct RHash {
     VALUE ifnone;
 };
 #define RHASH_TBL(h) rb_hash_tbl(h)
-#define RHASH_ITER_LEV(h) RHASH(h)->iter_lev
-#define RHASH_IFNONE(h) RHASH(h)->ifnone
+#define RHASH_ITER_LEV(h) (RHASH(h)->iter_lev)
+#define RHASH_IFNONE(h) (RHASH(h)->ifnone)
 #define RHASH_SIZE(h) (RHASH(h)->ntbl ? RHASH(h)->ntbl->num_entries : 0)
 #define RHASH_EMPTY_P(h) (RHASH_SIZE(h) == 0)