+test -d m4 || mkdir m4
+test -d lib || mkdir lib
+
+git submodule update --init || echo "Failed to update Gnulib sources from git."
+if test -x gnulib/gnulib-tool; then
+ gnulib/gnulib-tool --update || die "Failed to update gnulib."
+else
+ die "Gnulib sources are not properly installed in gnulib/"
+fi