sx: split out termination from cleanup handler

Due to the use of errexit when Xorg replied back to us with SIGUSR1 the
subshell would return an exit status of 128 + 10 (SIGUSR1)[1].

This combined with trap handlers not changing the exit value unless
explicitly done with exit $? means sx was always exiting with a status
of 138.

This change instead removes errexit and simply lets unset or erroneous
commands leak through until it hits a point where the combined errors
result in non-zero termination.

By splitting out the termination of Xorg to the end we can simply return
the return value from the last wait, which is the wait associated with
Xorg itself.

1. http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_28

sx

@@ -3,22 +3,12 @@
 
 # requires xauth Xorg
 
-# I'm willing to take advantage of errexit for this script as roughly 85% of
-# the error checking would just be exiting on command failure.
-set -o errexit
-
 cleanup() {
-    if kill -0 "$1" 2> /dev/null; then
-        kill -s TERM "$1"
-        wait "$1"
-    fi
-
     if ! stty "$stty"; then
         stty sane
     fi
 
     xauth remove :"$tty"
-    exit
 }
 
 stty=$(stty -g)
@@ -48,4 +38,10 @@ trap 'DISPLAY=:$tty "${@:-$cfgdir/sxrc}"' USR1
     trap '' USR1
     exec /usr/lib/xorg-server/Xorg :"$tty" -keeptty vt"$tty" -noreset -auth "$XAUTHORITY"
 ) & pid=$!
-wait
+
+wait "$pid"
+
+if kill -0 "$pid" 2> /dev/null; then
+    kill -s TERM "$pid"
+    wait "$pid"
+fi