tzdata: Make /etc/localtime a symbolic link

systemd-timedated wants this to be a symbolic link, cf. man 5 localtime.

> The /etc/localtime file configures the system-wide timezone of the
> local system that is used by applications for presentation to the
> user. It should be an absolute or relative symbolic link pointing to
> /usr/share/zoneinfo/, followed by a timezone identifier such as
> "Europe/Berlin" or "Etc/UTC". The resulting link should lead to the
> corresponding binary tzfile(5) timezone data for the configured
> timezone.
>
> Because the timezone identifier is extracted from the symlink target
> name of /etc/localtime, this file may not be a normal file or
> hardlink.

tzdata.be0

@@ -49,5 +49,5 @@ mee_install() {
     zic -d ${D}/${DATADIR}/zoneinfo -p America/New_York
 
     mkdir -pv ${D}${SYSCONFDIR}
-    cp ${D}${DATADIR}/zoneinfo/${MYTIMEZONE} ${D}${SYSCONFDIR}/localtime
+    ln -s ${D}${DATADIR}/zoneinfo/${MYTIMEZONE} ${D}${SYSCONFDIR}/localtime
 }