Issue #4258:  Make it possible to use 30-bit digits for PyLongs:
 - new configure option --enable-big-digits
 - new structseq sys.int_info giving information about the internal format
By default, 30-bit digits are enabled on 64-bit machines but
disabled on 32-bit machines.
diff --git a/Misc/NEWS b/Misc/NEWS
index 90b6091..3e890f3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,13 @@
 Core and Builtins
 -----------------
 
+- Issue #4258: Make it possible to use base 2**30 instead of base
+  2**15 for the internal representation of integers, for performance
+  reasons.  Base 2**30 is enabled by default on 64-bit machines.  Add
+  --enable-big-digits option to configure, which overrides the
+  default.  Add sys.int_info structseq to provide information about
+  the internal format.
+
 - Issue #4474: PyUnicode_FromWideChar now converts characters outside
   the BMP to surrogate pairs, on systems with sizeof(wchar_t) == 4
   and sizeof(Py_UNICODE) == 2.