merges r21813 from trunk into ruby_1_9_1.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21842 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r21813 from trunk into ruby_1_9_1.
test_complexrational.rb: [BUG] at IA-64 architecture
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21842 b2dd03c8-39d4-4d8f-98ff-823fe69b080e