merge revision(s) r40270:

	* struct.c (rb_struct_define_without_accessor, rb_struct_define),
	  (rb_struct_s_def): hide member names array.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@44970 b2dd03c8-39d4-4d8f-98ff-823fe69b080e