Update to the newest gnulib.

diff --git a/gnulib b/gnulib
index b5eb8780ffb06dbd633b667c1add43c8f7eb9b70..7e5312beab91ecc96211cdc3e5960af6908a2ed2 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit b5eb8780ffb06dbd633b667c1add43c8f7eb9b70
+Subproject commit 7e5312beab91ecc96211cdc3e5960af6908a2ed2