Update THANKS.
diff --git a/THANKS b/THANKS
index 6835db4..c7406b1 100644
--- a/THANKS
+++ b/THANKS
@@ -93,6 +93,7 @@
   - Martin Väth
   - Christian Weisgerber
   - Bert Wesarg
+  - Fredrik Wikstrom
   - Ralf Wildenhues
   - Charles Wilson
   - Lars Wirzenius