pack.c: use ivar for associated objects
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44804 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
pack.c: use ivar for associated objects
in an instance variables, instead of in the internal structure.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@44804 b2dd03c8-39d4-4d8f-98ff-823fe69b080e