merge #10968: commit threading doc changes and corresponding whatsnew entry.

It is unfortunate that the '_' names were not kept as aliases, and that RLock
was not also converted to a class, but it is now too late to change either of
those things for 3.3.

Doc/library/multiprocessing.rst

@@ -916,7 +916,7 @@ object -- see :ref:`multiprocessing-managers`.
 
 .. class:: Condition([lock])
 
-   A condition variable: a clone of :class:`threading.Condition`.
+   A condition variable: an alias for :class:`threading.Condition`.
 
    If *lock* is specified then it should be a :class:`Lock` or :class:`RLock`
    object from :mod:`multiprocessing`.

Doc/whatsnew/3.3.rst

@@ -1945,6 +1945,12 @@ of text  (:issue:`13857`).
 threading
 ---------
 
+:class:`threading.Condition`, :class:`threading.Semaphore`,
+:class:`threading.BoundedSempaphore`, :class:`threading.Event`, and
+:class:`threading.Timer`, all of which used to be factory functions returning a
+class instance, are now classes and may be subclassed. (Contributed by Éric
+Araujo in :issue:`109681`).
+
 The :class:`threading.Thread` constructor now accepts a ``daemon`` keyword
 argument to override the default behavior of inheriting the ``deamon`` flag
 value from the parent thread (:issue:`6064`).
@@ -2331,6 +2337,10 @@ Porting Python code
   make decisions affected by the AST version, use :attr:`sys.version_info`
   to make the decision.
 
+* Code that used to work around the fact that the :mod:`threading` module used
+  factory functions by subclassing the private classes will need to change to
+  subclass the now-public classes.
+
 
 Porting C code
 --------------

Misc/HISTORY

@@ -2907,11 +2907,11 @@ Library
 - Issue #8887: "pydoc somebuiltin.somemethod" (or help('somebuiltin.somemethod')
   in Python code) now finds the doc of the method.
 
-- Issue #10968: Remove indirection in threading.  The public names (Thread,
+- Issue #10968: Remove indirection in threading.  The public names (Event,
   Condition, etc.) used to be factory functions returning instances of hidden
-  classes (_Thread, _Condition, etc.), because (if Guido recalls correctly) this
-  code pre-dates the ability to subclass extension types.  It is now possible to
-  inherit from Thread and other classes, without having to import the private
+  classes (_Event, _Condition, etc.), because (if Guido recalls correctly) this
+  code pre-dates the ability to subclass extension types.  It is now possible
+  to inherit from these classes without having to import the private
   underscored names like multiprocessing did.
 
 - Issue #9723: Add shlex.quote functions, to escape filenames and command