[tz] latest zic mishandles Africa/Cairo past 2038?

[Paul Eggert]

When I run the command "make check_public" in the tz distribution,
several warnings are generated.  I'd like to fix things so that
it builds cleanly.  Let's start with the first warning:

"africa", line 190: warning: no POSIX environment variable for zone Africa/Cairo

As I understand it, this warning is saying that zic can't deduce
a POSIX-style TZ setting for Africa/Cairo time stamps predicted
past 2038.  But if you look at the data, there's a straightforward
POSIX-style setting for that, namely TZ='EET-2'.

My guess is that zic is confused because the most-recent Rule is for 2010.
Is my guess correct?  Is this a bug in zic.c, which can be fixed?