Ada.Calendar and NTP (and Unix Epoch)

[erlo <erlo@none>]

The following code raises an ADA.CALENDAR.TIME_ERROR exception:

with Calendar;
with Calendar.Conversions;
with Calendar.Arithmetic;
with Calendar.Formatting;
with Text_IO;
with Ada.Exceptions;

use Calendar;
use Text_IO;


procedure Main is
    AdaTid : Time;
begin
    AdaTid := Conversions.To_Ada_Time(tm_year  => 00,
                                      tm_mon   => 00,
                                      tm_day   => 01,
                                      tm_hour  => 0,
                                      tm_min   => 0,
                                      tm_sec   => 0,
                                      tm_isdst => 0); -- raises exception


    put_line(Formatting.Image(Date                  => AdaTid,
                              Include_Time_Fraction => False,
                              Time_Zone             => 0));

end Main;

This is because Ada.Calendar starts at 1-1-1901. But NTP starts at 
1-1-1900, so how can I work my way around this issue? I need to compare 
NTP time with Unix Epoch based time.

Erlo