Update to the newest gnulib.

diff --git a/gnulib b/gnulib
index 2923106da77d300a8385ca804daf9b8073f7edef..4d38340a76dbee56036a5fcc0f052ebcff616a59 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 2923106da77d300a8385ca804daf9b8073f7edef
+Subproject commit 4d38340a76dbee56036a5fcc0f052ebcff616a59