Issue #15819: Merge include search from 3.6

diff --cc Misc/NEWS
index 607c15fa95b5dc127cbd0feeaa53ab4243a6f286,34c3748ee4f5b14ab1337119f6e1fd847b60e3ae..ac89f65ad726428d3be76723b3ae6cfb83983460
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -13,17 -13,12 +13,23 @@@ Core and Builtin
  Library
  -------
  
+ Build
+ -----
+ 
+ - Issue #15819: Remove redundant include search directory option for building
+   outside the source tree.
+ 
 +Tools/Demos
 +-----------
 +
 +- Issue #15369: The pybench and pystone microbenchmark have been removed from
 +  Tools. Please use the new Python benchmark suite
 +  https://github.com/python/performance which is more reliable and includes a
 +  portable version of pybench working on Python 2 and Python 3.
 +
 +- Issue #28102: The zipfile module CLI now prints usage to stderr.
 +  Patch by Stephen J. Turnbull.
 +
  
  What's New in Python 3.6.0 beta 1
  =================================