??? What do you mean with "OS aware" here? "unaware"? I don't see the
relation to Debian and/or TeX Live.


OS independent as much as possible
2016-05-04  Karl Berry  <karl@freefriends.org>

        * texmfmp.c (init_start_time): new fn, factored out from
        initstarttime.
        (get_date_and_time): if envvar SOURCE_DATE_EPOCH_TEX_PRIMITIVES
        is set, initialize minutes, day, month, year, from
        SOURCE_DATE_EPOCH value.  Requested by Debian, thread starting at
        http://tug.org/pipermail/tex-k/2016-May/002691.html.

what happen if Windows decide to reserve  SOURCE_DATE_EPOCH for their own use ?
Is  SOURCE_DATE_EPOCH standard ?
And so on.

In any case, we (Hans nad me) are actively  discussing -- there are several points to check.

--
luigi