maint: pacify ‘make syntax-check’

Problem reported by Pádraig Brady (Bug#61386#226).
* src/split.c (parse_chunk): Use die instead of error.
(main): Quote a string.
* tests/local.mk (all_root_tests): Move du/apparent.sh from here ...
(all_tests): ... to here.

tests/local.mk

@@ -118,7 +118,6 @@ all_root_tests =				\
   tests/dd/skip-seek-past-dev.sh		\
   tests/df/problematic-chars.sh			\
   tests/df/over-mount-device.sh			\
-  tests/du/apparent.sh				\
   tests/du/bind-mount-dir-cycle.sh		\
   tests/du/bind-mount-dir-cycle-v2.sh		\
   tests/id/setgid.sh				\
@@ -557,6 +556,7 @@ all_tests =					\
   tests/df/total-verify.sh			\
   tests/du/2g.sh				\
   tests/du/8gb.sh				\
+  tests/du/apparent.sh				\
   tests/du/basic.sh				\
   tests/du/bigtime.sh				\
   tests/du/deref.sh				\