bpo-30450: Add NEWS and whatsnew (GH-2236)

Doc/whatsnew/3.7.rst

@@ -317,6 +317,12 @@ Build and C API Changes
   :c:func:`PyOS_AfterFork_Child`.  (Contributed by Antoine Pitrou in
   :issue:`16500`.)
 
+* The Windows build process no longer depends on Subversion to pull in external
+  sources, a Python script is used to download zipfiles from GitHub instead.
+  If Python 3.6 is not found on the system (via ``py -3.6``), NuGet is used to
+  download a copy of 32-bit Python for this purpose.  (Contributed by Zachary
+  Ware in :issue:`30450`.)
+
 
 Deprecated
 ==========

Misc/NEWS

@@ -1134,6 +1134,11 @@ IDLE
 Windows
 -------
 
+- bpo-30450: The build process on Windows no longer depends on Subversion,
+  instead pulling external code from GitHub via a Python script.  If Python 3.6
+  is not found on the system (via ``py -3.6``), NuGet is used to download a
+  copy of 32-bit Python.
+
 - bpo-29579: Removes readme.txt from the installer.
 
 - Issue #25778: winreg does not truncate string correctly (Patch by Eryk Sun)