require extension libraries. The patch is from nobu
  (Nobuyoshi Nakada).

* ext/thread/extconf.rb: for build ext/thread/thread.c.

* include/ruby/intern.h: ditto.

* thread.c: ditto.

* lib/thread.rb: removed and replaced by ext/thread/thread.c.

* ext/thread/thread.c: Queue, SizedQueue and ConditionVariable
  implementations in C. This patch is based on patches from panaggio
  (Ricardo Panaggio) and funny_falcon (Yura Sokolov) and  ko1
  (Koichi Sasada). [ruby-core:31513] [Feature #3620]

* test/thread/test_queue.rb (test_queue_thread_raise): add a test for
  ensuring that killed thread should be removed from waiting threads.
  It is based on a code by ko1 (Koichi Sasada). [ruby-core:45950]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e