Merge 3.3

diff --cc Doc/library/os.rst
Simple merge

diff --cc Misc/NEWS
index 422e6740970ef08c3b8c3d88ab3e137b5e236c8d,59ccb45e3b083a37c0adacf3ea1a4b8ea1872f5b..b44f1ae4bc95ebb6428e09e10672e2ac995f482b
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -152,6 -121,6 +152,9 @@@ Buil
  Documentation
  -------------
  
++- Issue #13498: Clarify docs of os.makedirs()'s exist_ok argument.  Done with
++  great native-speaker help from R. David Murray.
++
  - Issue #15533: Clarify docs and add tests for `subprocess.Popen()`'s cwd
    argument.