[anonymous] [bug #22017] zic can generate files which crash the linux kernel

[Paul Eggert]

<http://savannah.gnu.org/bugs/?22017> reports an interesting test case
whereby zic generates data that crashes the Linux kernel.  I thought
I'd forward it to this mailing list so that non-Linux people can hear
about it.

Here's the test case.  It makes the GNU C library tzfile.c fail
with an assertion that numtypes==1.

# /etc/timezone (auto-generated)

# Daylight savings time rules
#    Name       YrStart   YrEnd   Type   Month,Day,At,Offset      Letter
Rule DAYLIGHT   2000      max     -      Mar lastSun 02:00 01:00   -
Rule DAYLIGHT   2000      max     -      Oct lastSun 03:00 -01:00   -

# Timezone description
#    NAME        Offset    Rule       Name(/DaylightName)
Zone localtime   00:00     DAYLIGHT   GMT/BST