gc.c: use BUILTIN_TYPE
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52660 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
gc.c: use BUILTIN_TYPE
objects.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52660 b2dd03c8-39d4-4d8f-98ff-823fe69b080e