Update to newest gnulib.

diff --git a/gnulib b/gnulib
index 7f41a8405ac02cf00bc6bf775f604f638f938a18..6909b8edbea806a3bd50aa9baa600cdd3a0a760e 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 7f41a8405ac02cf00bc6bf775f604f638f938a18
+Subproject commit 6909b8edbea806a3bd50aa9baa600cdd3a0a760e