build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 6f6ca19e6cec9fec055258b1459108ef8822fe75..80b225fe1ea7d58848bf905dedaae8bb83872b45 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 6f6ca19e6cec9fec055258b1459108ef8822fe75
+Subproject commit 80b225fe1ea7d58848bf905dedaae8bb83872b45