Getting unexpected error from piping "read -d"

[Bart Schaefer <schaefer@brasslantern.com>]

This is a strange one, it only happens with "read -d" (change delimiter)
and only when piping the output.  It's present as far back as 4.3.11.

torch% read -d '' | head
zsh: bad tcgets: bad file descriptor

GDB trace from the current source is appended.

Incidentally, the oldest tagged version of zsh I can build from git is
4.3.10.  Any version 4.3.9 or older that I tried, generates pre-build
errors such as bad configure.ac files or failure to complete mkmakemod.
I suspect tags were incompletely or incorrectly applied when importing
from CVS.


(gdb) where
#0  gettyinfo (ti=0x816c780) at ../../zsh-5.0/Src/utils.c:1519
#1  0x080822eb in update_job (jn=0x87de894) at ../../zsh-5.0/Src/jobs.c:488
#2  0x080b6299 in wait_for_processes () at ../../zsh-5.0/Src/signals.c:512
#3  0x080b6493 in zhandler (sig=17) at ../../zsh-5.0/Src/signals.c:594
#4  <signal handler called>
#5  0x0086e7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#6  0x008afe8c in sigsuspend () from /lib/tls/libc.so.6
#7  0x080b603e in signal_suspend (sig=17, wait_cmd=0)
    at ../../zsh-5.0/Src/signals.c:375
#8  0x08084b41 in zwaitjob (job=1, wait_cmd=0) at ../../zsh-5.0/Src/jobs.c:1454
#9  0x08084d1a in waitjobs () at ../../zsh-5.0/Src/jobs.c:1499
#10 0x0806372f in execpline (state=0xbffe4f90, slcode=17410, how=18, last1=0)
    at ../../zsh-5.0/Src/exec.c:1554
#11 0x08062c33 in execlist (state=0xbffe4f90, dont_change_job=0, exiting=0)
    at ../../zsh-5.0/Src/exec.c:1261
#12 0x08062686 in execode (p=0xb7d3f6d0, dont_change_job=0, exiting=0, 
    context=0x813c803 "toplevel") at ../../zsh-5.0/Src/exec.c:1070
#13 0x0807d612 in loop (toplevel=1, justonce=0) at ../../zsh-5.0/Src/init.c:185
#14 0x08080927 in zsh_main (argc=2, argv=0xbffe50e4)
    at ../../zsh-5.0/Src/init.c:1625
#15 0x0804c0a6 in main (argc=2, argv=0xbffe50e4) at ../../zsh-5.0/Src/main.c:93