issue #535: update Changelog.

docs/changelog.rst

@@ -156,6 +156,13 @@ Core Library
   :class:`mitogen.service.Pool.defer` allows any function to be enqueued for
   the thread pool from another thread.
 
+* `#535 <https://github.com/dw/mitogen/issues/535>`_: a new
+  :mod:`mitogen.os_fork` module provides a :func:`os.fork` wrapper that pauses
+  all thread activity during a fork. :class:`mitogen.core.Broker` and
+  :class:`mitogen.service.Pool` automatically record their existence so that an
+  :func:`os.fork` monkey-patch activated for Python 2.4 and 2.5 can
+  automatically pause them for any attempt to start a subprocess.
+
 * `ca63c26e <https://github.com/dw/mitogen/commit/ca63c26e>`_:
   :meth:`mitogen.core.Latch.put`'s `obj` argument was made optional.