Update to the newest gnulib

diff --git a/gnulib b/gnulib
index 66f9edfa59dc1ae55a189fb9b647b7319b2a1b02..93b78ec081ff9e5be8f4cdcc44dd4f6f5da15164 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 66f9edfa59dc1ae55a189fb9b647b7319b2a1b02
+Subproject commit 93b78ec081ff9e5be8f4cdcc44dd4f6f5da15164