build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 8d605a54766b5495eb78bccad0d4f7ddc5d8537d..20074698382b7e4f049f52bbdeaf6a39508a8601 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 8d605a54766b5495eb78bccad0d4f7ddc5d8537d
+Subproject commit 20074698382b7e4f049f52bbdeaf6a39508a8601