(merge from 3.5) Issue #26662: Set PYTHON_FOR_GEN in configure

as the Python program to be used for file generation during the build.

diff --cc Makefile.pre.in
Simple merge

diff --cc Misc/NEWS
index 67ee5497d84dd022b8f25f7e52ae8cf333827d40,3ac2ed3400200653de54a2177fd831e78975dda4..3244f3b995b521feea82db631fdba7359a2938fa
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -56,52 -46,6 +56,58 @@@ Librar
  
  - Issue #27522: Avoid an unintentional reference cycle in email.feedparser.
  
 +- Issue 27512: Fix a segfault when os.fspath() called a an __fspath__() method
 +  that raised an exception. Patch by Xiang Zhang.
 +
 +Tests
 +-----
 +
 +- Issue #27472: Add test.support.unix_shell as the path to the default shell.
 +
 +- Issue #27369: In test_pyexpat, avoid testing an error message detail that
 +  changed in Expat 2.2.0.
 +
 +Windows
 +-------
 +
 +- Issue #27610: Adds PEP 514 metadata to Windows installer
 +
 +- Issue #27469: Adds a shell extension to the launcher so that drag and drop
 +  works correctly.
 +
 +- Issue #27309: Enables proper Windows styles in python[w].exe manifest.
 +
++Build
++-----
++
++- Issue #26662: Set PYTHON_FOR_GEN in configure as the Python program to be
++  used for file generation during the build.
++
 +What's New in Python 3.6.0 alpha 3
 +==================================
 +
 +*Release date: 2016-07-11*
 +
 +Core and Builtins
 +-----------------
 +
 +- Issue #27473: Fixed possible integer overflow in bytes and bytearray
 +  concatenations.  Patch by Xiang Zhang.
 +
 +- Issue #23034: The output of a special Python build with defined COUNT_ALLOCS,
 +  SHOW_ALLOC_COUNT or SHOW_TRACK_COUNT macros is now off by  default.  It can
 +  be re-enabled using the "-X showalloccount" option.  It now outputs to stderr
 +  instead of stdout.
 +
 +- Issue #27443: __length_hint__() of bytearray iterators no longer return a
 +  negative integer for a resized bytearray.
 +
 +- Issue #27007: The fromhex() class methods of bytes and bytearray subclasses
 +  now return an instance of corresponding subclass.
 +
 +Library
 +-------
 +
  - Issue #26844: Fix error message for imp.find_module() to refer to 'path'
    instead of 'name'. Patch by Lev Maximov.
  

diff --cc configure
Simple merge

diff --cc configure.ac
Simple merge