build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 4f7dce3fc20179ed6c24b7d84b82a99b6f410fef..fb034b35eb0efe3ac0a42ca34f90927c4d29d630 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 4f7dce3fc20179ed6c24b7d84b82a99b6f410fef
+Subproject commit fb034b35eb0efe3ac0a42ca34f90927c4d29d630