build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 8524167df6555c38079e9d041044dc59a9ddbeee..45cb2a14a68a519bfa57abfa1751cde6150b6f81 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 8524167df6555c38079e9d041044dc59a9ddbeee
+Subproject commit 45cb2a14a68a519bfa57abfa1751cde6150b6f81