Update to the newest gnulib.

diff --git a/gnulib b/gnulib
index 1aee1fe7d5a1d8a1f2067c4eede0a34bd1e3a655..99ddb8cef8f6f61adf3a571348b875d86a5368eb 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 1aee1fe7d5a1d8a1f2067c4eede0a34bd1e3a655
+Subproject commit 99ddb8cef8f6f61adf3a571348b875d86a5368eb