build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 7424e3cfaa7d4380e3c3a8658dc693579ffb1ff5..d79e2998ca2c2c38439533306312e79f5d86cf68 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 7424e3cfaa7d4380e3c3a8658dc693579ffb1ff5
+Subproject commit d79e2998ca2c2c38439533306312e79f5d86cf68