Merged in ncoghlan/cpython350 (pull request #17)

diff --cc Misc/NEWS
index 11d7de4225ae0ddc53eecb322892c175d2adc3dc,7ea23875310467a0bbbf7c0876a69a2ab26b8e91..ba24851f11e6100dfecbc20ace19c026d5d5e43f
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -17,8 -15,11 +17,13 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #24748: To resolve a compatibility problem found with py2exe and
+   pywin32, imp.load_dynamic() once again ignores previously loaded modules
+   to support Python modules replacing themselves with extension modules.
+   Patch by Petr Viktorin.
+ 
 +- Issue #24917: time_strftime() Buffer Over-read. Patch by John Leitch.
 +
  - Issue #24635: Fixed a bug in typing.py where isinstance([], typing.Iterable)
    would return True once, then False on subsequent calls.