Issue #6915: Under Windows, os.listdir() didn't release the Global
Interpreter Lock around all system calls.  Original patch by Ryan Kelly.
diff --git a/Misc/ACKS b/Misc/ACKS
index 41d314e..6f689ad 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -419,6 +419,7 @@
 Lou Kates
 Hiroaki Kawai
 Sebastien Keim
+Ryan Kelly
 Robert Kern
 Randall Kern
 Magnus Kessler