bpo-27945: Fixed various segfaults with dict. (#1657)

Based on patches by Duane Griffin and Tim Mitchell.
diff --git a/Misc/ACKS b/Misc/ACKS
index d00fa79..098c801 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -546,6 +546,7 @@
 Kim Gräsman
 Nathaniel Gray
 Eddy De Greef
+Duane Griffin
 Grant Griffin
 Andrea Griffini
 Duncan Grisby