Bug report: PWD environment variable broken!

[Martin Buchholz <martin@xxxxxxxxxx>]

On some platforms, the PWD environment variable is not being properly
updated after a cd.  This is the environment variable, not the
internal PWD variable.

Here is some output on a variety of systems for this command sequence:

uname -a; echo $ZSH_VERSION; cd ~/x/build;  env | grep PWD | grep -v OLDPWD

Conclusions:  3.1 Seems to be broken on Linux and BSDI.  A serious bug.

I tried to downgrade to 3.0.5.

3.0.5 on BSDI coredumps on invocation. 

On Linux 3.0.5 failed to build:

gcc -c -I.. -I. -I.  -DHAVE_CONFIG_H -Wall -Wno-implicit -Wmissing-prototypes -O2 builtin.c
builtin.c:4279: macro `dup' used with just one arg

:-(

It's sad to see my favorite shell so buggy!

-------------- etlindy11 ----------------
IRIX etlindy11 6.2 03131015 IP22
3.1.5
PWD=/usr/users/martin/x/build
-------------- etlsui2  ----------------
HP-UX etlsui2 B.10.20 A 9000/780 2004436110 two-user license
3.1.5
PWD=/usr/users/martin/x/build
-------------- mongkok  ----------------
Linux mongkok 2.0.34 #5 Tue Feb 16 17:22:05 JST 1999 i586 unknown
3.1.2-debian
PWD=/usr/users/martin
-------------- mule     ----------------
SunOS mule 4.1.4 2 sun4m
3.1.5
PWD=/usr/users/martin/x/build
-------------- etlken   ----------------
SunOS etlken 5.6 Generic_105181-08 sun4u sparc SUNW,Ultra-2
3.1.5
PWD=/usr/users/martin/x/build
-------------- gneiss   ----------------
OSF1 gneiss.etl.go.jp V4.0 1091 alpha
3.1.5
PWD=/usr/users/martin/x/build
-------------- yuenlong ----------------
export DISPLAY=mulelab:0.0
uname -a; echo $ZSH_VERSION; cd ~/x/build;  env | grep PWD
FreeBSD yuenlong.etl.go.jp 2.2.8-RELEASE FreeBSD 2.2.8-RELEASE #0: Mon Nov 30 06:34:08 GMT 1998     jkh@xxxxxxxxxxxxxx:/usr/src/sys/compile/GENERIC  i386
3.0.5
PWD=/usr/users/martin/x/build
-------------- kowloon  ----------------
export DISPLAY=mulelab:0.0
uname -a; echo $ZSH_VERSION; cd ~/x/build;  env | grep PWD
BSD/OS kowloon.etl.go.jp 4.0 BSDI BSD/OS 4.0 Kernel #0: Tue Jul 28 15:56:54 MDT 1998     polk@xxxxxxxxxxxxxxxxx:/rel/proto/4.0-i386/usr/src/sys/compile/GENERIC  i386
3.1.5
PWD=/usr/home/martin
-------------- mulelab  ----------------
SunOS mulelab 5.5.1 Generic_103640-05 sun4u sparc SUNW,Ultra-2
3.1.5
PWD=/usr/users/martin/x/build