* lib/logger.rb: Inter-process locking for log rotation
  Current implementation fails log rotation on multi process env.
  by sonots <sonots@gmail.com>
  https://github.com/ruby/ruby/pull/428 fix GH-428 [Bug #9046]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43511 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-11-02

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43512 b2dd03c8-39d4-4d8f-98ff-823fe69b080e