build: update gnulib to latest

diff --git a/gnulib b/gnulib
index 6a978b7d2febb63a6b538a1d3f428607c49a8ae4..451042cb76d3f78f070c27ce8af6b6d215354681 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 6a978b7d2febb63a6b538a1d3f428607c49a8ae4
+Subproject commit 451042cb76d3f78f070c27ce8af6b6d215354681