build: update gnulib submodule to latest

* gnulib: Update with various build/test fixes.

diff --git a/gnulib b/gnulib
index c610b4a9b289cb99dc78178a233b811614af9c26..82edd0e68b9e88fb24c1d32ad815083f66fae1ef 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit c610b4a9b289cb99dc78178a233b811614af9c26
+Subproject commit 82edd0e68b9e88fb24c1d32ad815083f66fae1ef