Ruby » Ruby master

merges r30743 from trunk into ruby_1_9_2.¶

    * thread.c (thread_start_func_2): check deadlock condition before
      release thread stack. fix memory violation when deadlock detected.
      reported by Max Aller. [Bug #4009] [ruby-core:32982]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@31202 b2dd03c8-39d4-4d8f-98ff-823fe69b080e