Update gnulib.

diff --git a/gnulib b/gnulib
index 86725346a1b116f3c2da26c124288f5f4495bf69..f40e61ea0c4940b027aade7dd48948aa93f133a4 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 86725346a1b116f3c2da26c124288f5f4495bf69
+Subproject commit f40e61ea0c4940b027aade7dd48948aa93f133a4