faulthandler: Restore the old sigaltstack during teardown (#777)

diff --git a/Misc/ACKS b/Misc/ACKS
index c99aeaa..2056efe 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
Binary files differ
diff --git a/Misc/NEWS b/Misc/NEWS
index 97c45d4..8cc8b9f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -287,6 +287,9 @@
 Library
 -------
 
+- bpo-29884: faulthandler: Restore the old sigaltstack during teardown.
+  Patch by Christophe Zeitouny.
+
 - bpo-25455: Fixed crashes in repr of recursive buffered file-like objects.
 
 - bpo-29800: Fix crashes in partial.__repr__ if the keys of partial.keywords