build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index d8f90adf5f01512958b6da46bd5eea01294a434e..696aa74b38f8c109c21e4c01194faab53fb4cefc 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit d8f90adf5f01512958b6da46bd5eea01294a434e
+Subproject commit 696aa74b38f8c109c21e4c01194faab53fb4cefc