build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index cda5c90820d55b4b1f52d6a6f5329a10668bd720..12335899d0089131d854aa1b074f0c4d841dff42 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit cda5c90820d55b4b1f52d6a6f5329a10668bd720
+Subproject commit 12335899d0089131d854aa1b074f0c4d841dff42