Update to the newest gnulib.

diff --git a/gnulib b/gnulib
index a9447b51ea6d87507b1e853023c7adc428267ece..bbf0d3fdf25e8f85c7751ac0ee90a0f50a0f054d 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit a9447b51ea6d87507b1e853023c7adc428267ece
+Subproject commit bbf0d3fdf25e8f85c7751ac0ee90a0f50a0f054d