build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index a92aa179978a136fa9cc9023d02b5529b19a2210..0a12fa9db035ede86f361409108f0d4a6adce0b9 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit a92aa179978a136fa9cc9023d02b5529b19a2210
+Subproject commit 0a12fa9db035ede86f361409108f0d4a6adce0b9