Update to newest gnulib.

diff --git a/gnulib b/gnulib
index 478a626cc68430e9db0ebd19166a28eb30ed431b..4cfff6810c595e60cf4411dc9bac83c0328e8812 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 478a626cc68430e9db0ebd19166a28eb30ed431b
+Subproject commit 4cfff6810c595e60cf4411dc9bac83c0328e8812