diff --git a/projects/OS400/os400sys.c b/projects/OS400/os400sys.c
index 207eb297bb..41f0f670e7 100644
--- a/projects/OS400/os400sys.c
+++ b/projects/OS400/os400sys.c
@@ -1035,4 +1035,4 @@ int Curl_os400_inflateEnd(z_streamp strm)
   return ret;
 }
 
-#endif
+#endif /* HAVE_LIBZ */