merges r22322 from trunk into ruby_1_9_1.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@22535 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merges r22322 from trunk into ruby_1_9_1.
with VC9. [ruby-core:22115]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@22535 b2dd03c8-39d4-4d8f-98ff-823fe69b080e