build: update to latest gnulib

* .gnulib: Update to latest, for more strerror_r fixes.

diff --git a/.gnulib b/.gnulib
index 9d196fad055a448c5732a8e950cc044b353d2615..5bf7fda437a10cc10cbd1be1bd06b374a581f0dd 160000 (submodule)
--- a/.gnulib
+++ b/.gnulib
@@ -1 +1 @@
-Subproject commit 9d196fad055a448c5732a8e950cc044b353d2615
+Subproject commit 5bf7fda437a10cc10cbd1be1bd06b374a581f0dd