Issue #9516: Merge Distutils changes from 3.2

diff --cc Misc/NEWS
index ae17169e033f538ce82b28d1489409091cd0de3e,834dea6487ff806903c7264cec2ac2627d7fb52d..de3026bc6bad6508c4abdbb6aff34ed82e8a1a57
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -200,11 -25,17 +200,22 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #9516: On Mac OS X, change Distutils to no longer globally attempt to
+   check or set the MACOSX_DEPLOYMENT_TARGET environment variable for the
+   interpreter process.  This could cause failures in non-Distutils subprocesses
+   and was unreliable since tests or user programs could modify the interpreter
+   environment after Distutils set it.  Instead, have Distutils set the the
+   deployment target only in the environment of each build subprocess.  It is
+   still possible to globally override the default by setting
+   MACOSX_DEPLOYMENT_TARGET before launching the interpreter; its value must be
+   greater or equal to the default value, the value with which the interpreter
+   was built.
+ 
 +- Issue #12422: In the copy module, don't store objects that are their own copy
 +  in the memo dict.
 +
 +- Issue #12303: Add sigwaitinfo() and sigtimedwait() to the signal module.
 +
  - Issue #12404: Remove C89 incompatible code from mmap module. Patch by Akira
    Kitada.