* marshal.c (w_object, marshal_dump, r_object0, marshal_load): search
	  public methods only.  [ruby-core:17283]
	* object.c (convert_type): ditto.
	* lib/singleton.rb (Singleton#_dump): conversion method should be
	  public.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8_7@17852 b2dd03c8-39d4-4d8f-98ff-823fe69b080e