Skip signal handler re-installation if it is not necessary.  Issue 8354.
diff --git a/Misc/NEWS b/Misc/NEWS
index 8a471df..ac28fad 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -96,6 +96,9 @@
 - Issue #4687: Fix accuracy of garbage collection runtimes displayed with
   gc.DEBUG_STATS.
 
+- Issue #8354: The siginterrupt setting is now preserved for all signals,
+  not just SIGCHLD.
+
 - Issue #7192: webbrowser.get("firefox") now wors on Mac OS X, as does
   webbrowser.get("safari").