merge 3.2 (#12878)

diff --cc Lib/test/test_io.py
Simple merge

diff --cc Misc/NEWS
index 215bc849f798f45af38ff0a2e028ac147eeb5e99,514d19afedd2846b200449593c3fb6e244cced54..662efe7c61fe4fc2a329acd02d669d1edfd8cf16
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -271,17 -28,12 +271,19 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #12878: Expose a __dict__ attribute on io.IOBase and its subclasses.
+ 
  - Issue #12636: IDLE reads the coding cookie when executing a Python script.
  
 +- Issue #12494: On error, call(), check_call(), check_output() and
 +  getstatusoutput() functions of the subprocess module now kill the process,
 +  read its status (to avoid zombis) and close pipes.
 +
 +- Issue #12720: Expose low-level Linux extended file attribute functions in os.
 +
  - Issue #10946: The distutils commands bdist_dumb, bdist_wininst and bdist_msi
 -  now respect a --skip-build option given to bdist.
 +  now respect a --skip-build option given to bdist.  The packaging commands
 +  were fixed too.
  
  - Issue #12847: Fix a crash with negative PUT and LONG_BINPUT arguments in
    the C pickle implementation.