* eval.c (umethod_bind): recv can be an instance of descender of
  oklass if oklass is a Module.

* hash.c (rb_hash_equal): check identiry equality first.

* variable.c (mod_av_set): detect constant overriding for built-in
  classes/modules.

* marshal.c (w_object): should retrieve __member__ data from
  non-singleton class.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_6@1706 b2dd03c8-39d4-4d8f-98ff-823fe69b080e