Py_buffer.obj field.

a lookup.

"if you want to make a sandbox on top of CPython, you have to fix segfaults"
so let's fix segfaults!

Also, add a multiprocessing.connection.wait(rlist, timeout=None) function
for polling multiple objects at once.  Patch by sbt.

Complete changelist from sbt's patch:

* Adds a wait(rlist, timeout=None) function for polling multiple
  objects at once.  On Unix this is just a wrapper for
  select(rlist, [], [], timeout=None).

* Removes use of the SentinelReady exception and the sentinels argument
  to certain methods.  concurrent.futures.process has been changed to
  use wait() instead of SentinelReady.

* Fixes bugs concerning PipeConnection.poll() and messages of zero
  length.

* Fixes PipeListener.accept() to call ConnectNamedPipe() with
  overlapped=True.

* Fixes Queue.empty() and SimpleQueue.empty() so that they are
  threadsafe on Windows.

* Now PipeConnection.poll() and wait() will not modify the pipe except
  possibly by consuming a zero length message.  (Previously poll()
  could consume a partial message.)

* All of multiprocesing's pipe related blocking functions/methods are
  now interruptible by SIGINT on Windows.

not adhere to the new documentation and b) manage to clobber view->obj before
returning failure.

Some minidom code changed between 3.2 and 3.3, so to be sure to avoid
differenced in behavior I’m backporting these tests added by MvL.

Patch by Ralf Schmitt.

I assume that most users looking at this page are looking for a library
to process XML, not a low-level parser.  First proposed in #11379.