system: propagate error in rc.syshook scripts #6594

We could stop on first problem but that woul likely break a number
of setups that use boot early/start hooks with sloppy coding.

Instead make the full run as an error and report it at the end.

src/etc/rc.halt

@@ -1,5 +1,6 @@
 #!/bin/sh
 
+# shutdown syshook / plugin scripts
 /usr/local/etc/rc.syshook stop
 
 /sbin/shutdown -op now

src/etc/rc.syshook

@@ -59,6 +59,7 @@ if [ ! -d ${SYSDIR}/${SYSLEVEL} ]; then
 fi
 
 SYSHOOKS="$(find -s ${SYSDIR}/${SYSLEVEL} -type f})"
+RETURN=0
 
 for _SYSHOOK in ${SYSHOOKS}; do
 	SYSHOOK=${_SYSHOOK##"${SYSDIR}/"}
@@ -69,7 +70,8 @@ for _SYSHOOK in ${SYSHOOKS}; do
 
 	if ! ${_SYSHOOK} "${@}"; then
 		echo ">>> Error in ${SYSLEVEL} script '${SYSNAME}'"
+		RETURN=1
 	fi
 done
 
-exit 0
+exit ${RETURN}