Issue #15819: Fix out-of-tree builds from a readonly source.
diff --git a/Misc/NEWS b/Misc/NEWS
index 1b7f80f..f13499f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -364,6 +364,9 @@
 Build
 -----
 
+- Issue #15819: Make sure we can build Python out-of-tree from a readonly
+  source directory.  (Somewhat related to Issue #9860.)
+
 - Issue #15645: Ensure 2to3 grammar pickles are properly installed.
 
 - Issue #15560: Fix building _sqlite3 extension on OS X with an SDK.