Running "2.3.6.ds1-8" from Debian unstable on x86_64, libc does not seem to
correctly update its idea of localtime when /etc/localtime changes.

adi@xxxxx:~/tmp$ cat localtime-relink.c
#include <time.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    char b1[40], b2[40];
    time_t t;
    struct tm tm1, tm2;

    system("ln -snf /usr/share/zoneinfo/PST8PDT /etc/localtime");
    system("ls -l /etc/localtime");

    t = 1192516347;
    strftime(b1, sizeof(b1), "%F %T %Z", localtime_r(&t, &tm1));

    system("ln -snf /usr/share/zoneinfo/EST5EDT /etc/localtime");
    system("ls -l /etc/localtime");

    t = 1192516347;
    strftime(b2, sizeof(b2), "%F %T %Z", localtime_r(&t, &tm2));

    printf("b1 = %s\n", b1);
    printf("b2 = %s\n", b2);

    return 0;
}
adi@xxxxx:~/tmp$ cc -Wall -g localtime-relink.c
adi@xxxxx:~/tmp$ sudo ./a.out
lrwxrwxrwx 1 root root 27 2007-10-15 23:56 /etc/localtime ->
/usr/share/zoneinfo/PST8PDT
lrwxrwxrwx 1 root root 27 2007-10-16 02:56 /etc/localtime ->
/usr/share/zoneinfo/EST5EDT
b1 = 2007-10-15 23:32:27 PDT
b2 = 2007-10-15 23:32:27 PDT

Note that the ls output does have the proper timezone offset, but the two calls
to localtime_r return the same 'struct tm' values.  Inspecting with gdb shows
that all fields are the same.