bin/51484: Build on Linux host fails due to nbzic crash

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         51484
>Category:       bin
>Synopsis:       Build on Linux host fails due to nbzic crash
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Sep 18 08:45:00 +0000 2016
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2016.09.17.20.48.04
>Organization:

>Environment:
System: NetBSD
Architecture: i386
Machine: i386
>Description:

My nightly build of NetBSD-current/i386 on a Linux/amd64 (Debian 7)
host is failing, with the nbzic tool printing the following backtrace:

  --- install-tz ---
  ======= Backtrace: =========
  /lib/x86_64-linux-gnu/libc.so.6(+0x75bb6)[0x7fb982486bb6]
  /lib/x86_64-linux-gnu/libc.so.6(cfree+0x6c)[0x7fb98248b95c]
  /bracket/build/2016.09.17.20.48.04-i386/tools/bin/nbzic[0x405103]
  /bracket/build/2016.09.17.20.48.04-i386/tools/bin/nbzic[0x4060e8]
  /bracket/build/2016.09.17.20.48.04-i386/tools/bin/nbzic[0x406b76]
  /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xfd)[0x7fb98242fead]
  /bracket/build/2016.09.17.20.48.04-i386/tools/bin/nbzic[0x401139]

More log data at:

  http://www.gson.org/netbsd/bugs/build/i386-linuxhost/2016/2016.09.17.20.48.04/build.log.tail

I can't determine the offending commit by automated bisection as
the problem appeared during a period when the build was already 
broken, but I'm guessing it's this one:

  2016.09.16.17.12.06 christos src/lib/libc/time/Makefile 1.33
  2016.09.16.17.12.06 christos src/lib/libc/time/NEWS 1.16
  2016.09.16.17.12.06 christos src/lib/libc/time/Theory 1.20
  2016.09.16.17.12.06 christos src/lib/libc/time/tz-art.htm 1.13
  2016.09.16.17.12.06 christos src/lib/libc/time/tz-how-to.html 1.1
  2016.09.16.17.12.06 christos src/lib/libc/time/tz-link.htm 1.26
  2016.09.16.17.12.06 christos src/lib/libc/time/zic.c 1.59

>How-To-Repeat:

Try to build -current on Debian 7.

>Fix: