Expose Subversion revision number (calculated via "svnversion .") to Python.
Add C API function Py_GetBuildNumber(), add it to the interactive prompt
banner (i.e. Py_GetBuildInfo()), and add it as the sys.build_number
attribute.  The build number is a string instead of an int because it may
contain a trailing 'M' if there are local modifications.
diff --git a/Misc/NEWS b/Misc/NEWS
index bd00491..d4aaa74 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,10 @@
 Core and builtins
 -----------------
 
+- Patch #1382163: Expose Subversion revision number to Python.  New C API
+  function Py_GetBuildNumber().  New attribute sys.build_number.  Build number
+  is now displayed in interactive prompt banner.
+
 - Implementation of PEP 341 - Unification of try/except and try/finally.
   "except" clauses can now be written together with a "finally" clause in
   one try statement instead of two nested ones.  Patch #1355913.