thread_pthread.c: variable for errno

* thread_pthread.c (rb_thread_wakeup_timer_thread_fd): use a local
  variable for errno.

* thread_pthread.c (consume_communication_pipe): ditto.  add
  EWOULDBLOCK case.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45909 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2014-05-11

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45910 b2dd03c8-39d4-4d8f-98ff-823fe69b080e