build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index f4919b224dd1545190f35eb481f78694f2337cb1..a7f1fa01c17b43898c702eff478c4c2b6293e9c7 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit f4919b224dd1545190f35eb481f78694f2337cb1
+Subproject commit a7f1fa01c17b43898c702eff478c4c2b6293e9c7