marshal.c: GC guard
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38174 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
marshal.c: GC guard
RB_GC_GUARD() (directly or indirectly) instead of volatile.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38174 b2dd03c8-39d4-4d8f-98ff-823fe69b080e