diff --git a/NEWS b/NEWS
index bb89349..6c76916 100644
--- a/NEWS
+++ b/NEWS
@@ -8,7 +8,7 @@ NEWS
   error_one_per_line was used and suppressed a message, then error_at_line()
   didn't exit.
 - Fix race condition when using threads. The fix requires thread-local
-  storage.
+  storage (available on at least GNU/Linux and FreeBSD).
 - Documentation updates.