Merge 3.6 (issue #28369)

diff --cc Misc/NEWS
index d5e50f07f6be973553a794ad9e2114369a5ca489,cdd68f6913e731f00f6007e3362b5760fada6b56..17ae6eaf0a30c655d8734694389bae7a51cb7c27
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -172,12 -163,13 +172,15 @@@ Librar
  - Issue #27759: Fix selectors incorrectly retain invalid file descriptors.
    Patch by Mark Williams.
  
 -- Issue #28368: Refuse monitoring processes if the child watcher has no
 -  loop attached.
 +- Issue #28325: Remove vestigal MacOS 9 macurl2path module and its tests.
 +
 +- Issue #28368: Refuse monitoring processes if the child watcher has
 +  no loop attached.
    Patch by Vincent Michel.
  
+ - Issue #28369: Raise RuntimeError when transport's FD is used with
+   add_reader, add_writer, etc.
+ 
  Windows
  -------