all: fix program name with --enable-single-binary=shebangs

* gnulib: Pick up gnulib commit f11caad4fd which ensures
we diagnose the actual utility name, and not just "coreutils"
when in single binary mode.  This adjustment is required
since gnulib commit 959152ba37 which enforced use of gnulib's
error() once verror is used, and gnulib's error() always
outputs the base name of the command, which the new gnulib
commit now keeps up to date.

diff --git a/gnulib b/gnulib
index 05c63bc908a67a316fea29ddf4c702d89cf5bdec..f11caad4fd70701bd1d95691a8528617623bf121 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 05c63bc908a67a316fea29ddf4c702d89cf5bdec
+Subproject commit f11caad4fd70701bd1d95691a8528617623bf121