Set make flags also on BUILD(), otherwise tzselect ended up with
the wrong location for TZDIR.
Previous version failed with:
`/bin/tzselect: time zone files are not set up correctly`
Now it finds the files ok, but trying to use it further causes
/bin/date to crash around 7 times in a row (?! UPDATE: fixed in hrev57356).
`> zdump -v America/Buenos_Aires` also works now, while previously
failed with:
`America/Buenos_Aires: No such file or directory`,
or with:
```
> ln -s /boot/system/data/zoneinfo/America/Buenos_Aires /etc/localtime
> zdump -v /etc/localtime
/etc/localtime: No error
```
Now the latter also works OK.
