Update to the newest gnulib.

diff --git a/gnulib b/gnulib
index 4ca39f72e42d04184a97ac28d284a3039723e76e..4b11de31a3b3e81b9c3a0b12c9f2924aefa1d84e 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 4ca39f72e42d04184a97ac28d284a3039723e76e
+Subproject commit 4b11de31a3b3e81b9c3a0b12c9f2924aefa1d84e