Issue #28918: Merge 3.6.

diff --cc Misc/NEWS
index bb120e545ba40a5856c7c17713310cabb16ffcb8,587c4d24bd58e5594e34a5f271bd893e0928bcaf..48ce4bdfd0f6905c5e093bb6d05f71c801b6172e
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -10,6 -10,12 +10,9 @@@ What's New in Python 3.7.0 alpha 
  Core and Builtins
  -----------------
  
 -- Issue #28731: Optimize _PyDict_NewPresized() to create correct size dict.
 -  Improve speed of dict literal with constant keys up to 30%.
 -
+ - Issue #28918: Fix the cross compilation of xxlimited when Python has been
+   built with Py_DEBUG defined.
+ 
  - Issue #5322: Fixed setting __new__ to a PyCFunction inside Python code.
    Original patch by Andreas Stührk.
  

diff --cc setup.py
Simple merge