git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@26021 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
extension commands with optional parameters have been broken because of
a spec change of UnboundMethod#arity.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@26021 b2dd03c8-39d4-4d8f-98ff-823fe69b080e