build: update gnulib submodule to latest

Primarily to get the new cpu-supports module.

diff --git a/gnulib b/gnulib
index 68ecc26f30b284a26ab9aa0a08299869ea713c71..4aa11814c9e9979b82e07c8793723d50ac183920 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 68ecc26f30b284a26ab9aa0a08299869ea713c71
+Subproject commit 4aa11814c9e9979b82e07c8793723d50ac183920