Issue #12839: Fix crash in zlib module due to version mismatch.
If the version of zlib used to compile the zlib module is incompatible
with the one that is actually linked in, then calls into zlib will fail.
This can leave attributes of the z_stream uninitialized, so we must take
care to avoid segfaulting by trying to use an invalid pointer.
Fix by Richard M. Tew.
diff --git a/Misc/ACKS b/Misc/ACKS
index 6f7d9d1..7096d72 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -874,6 +874,7 @@
Amy Taylor
Anatoly Techtonik
Mikhail Terekhov
+Richard M. Tew
Tobias Thelen
James Thomas
Robin Thomas