bin/41864: /bin/sh's wait built-in returns wrong exit status

[ekamperi%gmail.com@localhost]

>Number:         41864
>Category:       bin
>Synopsis:       /bin/sh's wait built-in returns wrong exit status
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Aug 10 09:20:00 +0000 2009
>Originator:     Stathis Kamperis
>Release:        NetBSD 5.0_STABLE
>Organization:
Aristotle University of Thessaloniki
>Environment:
NetBSD voyager 5.0_STABLE NetBSD 5.0_STABLE (MYGENERIC) #9: Wed Aug  5 00:38:20 
EEST 2009  root@voyager:/usr/obj/sys/arch/i386/compile/MYGENERIC i386

>Description:
~% cat lala.sh
#!/usr/pkg/bin/bash

true &
pid=$!
sleep 1

wait $pid
echo $?
~% ./lala.sh
0
~% cat lala.sh
#!/bin/sh

true &
pid=$!
sleep 1

wait $pid
echo $?
~% ./lala.sh
127               <--- this shouldn't happen
~% 

If I remove the sleep command, sh returns the right exit status.
I guess it has trouble remembering the exit status of an arbitrary command 
invocation,
if between that command and the call to wait, another command is interpolated.

In DragonFlyBSD that I checked, it works ok (both bash and sh return the same 
exit status).
>How-To-Repeat:

>Fix: