#12890: fix test on windows

Patch by Stephen Tonkin.
diff --git a/Misc/ACKS b/Misc/ACKS
index 1db8194..d80ead0 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1174,6 +1174,7 @@
 R Lindsay Todd
 Eugene Toder
 Erik Tollerud
+Stephen Tonkin
 Matias Torchinsky
 Sandro Tosi
 Richard Townsend