gnulib: update to latest

diff --git a/gnulib b/gnulib
index c7d0b4506574887be5835ae9ae892d365afbb98c..8524167df6555c38079e9d041044dc59a9ddbeee 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit c7d0b4506574887be5835ae9ae892d365afbb98c
+Subproject commit 8524167df6555c38079e9d041044dc59a9ddbeee