make-snapshot: rubyarchdir

* tool/make-snapshot (package): fake rubyarchdir too.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39150 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
make-snapshot: File.join

* tool/make-snapshot (package): use File.join to get rid of continuous
  slashes.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39151 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
make-snapshot: fix typo

* tool/make-snapshot (package): fix typo, liburyb, in fake
  config.status.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39152 b2dd03c8-39d4-4d8f-98ff-823fe69b080e