git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@24294 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r24229 and r24233 from trunk into ruby_1_9_1.¶
IRB::irb_at_exit. no use finalizer saving history. [ruby-dev-38563]
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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@24294 b2dd03c8-39d4-4d8f-98ff-823fe69b080e