[tz] historic Oslo times

[Paul Eggert]

Meno Hochschild wrote:
> The rule for 1940 cannot be applied because 1st of Apr is clearly before the
> UNTIL-date of zone line in question when changing from Norway-rule to C-Eur-rule.

When a zone switches from one set of rules to another, the rule in effect at the 
time of the switch is the rule that governs, even if this rule first took effect 
before the switch.  So the rule you mention can be applied, and the data for 
Europe/Oslo should be OK.  You can verify this by running the command "zdump -v 
Europe/Oslo" and verifying that all the transitions are as expected.  Here are 
the war-year transitions that I observed that way:

Sat Aug 10 21:59:59 1940 UT = Sat Aug 10 22:59:59 1940 CET isdst=0 gmtoff=3600
Sat Aug 10 22:00:00 1940 UT = Sun Aug 11 00:00:00 1940 CEST isdst=1 gmtoff=7200
Mon Nov  2 00:59:59 1942 UT = Mon Nov  2 02:59:59 1942 CEST isdst=1 gmtoff=7200
Mon Nov  2 01:00:00 1942 UT = Mon Nov  2 02:00:00 1942 CET isdst=0 gmtoff=3600
Mon Mar 29 00:59:59 1943 UT = Mon Mar 29 01:59:59 1943 CET isdst=0 gmtoff=3600
Mon Mar 29 01:00:00 1943 UT = Mon Mar 29 03:00:00 1943 CEST isdst=1 gmtoff=7200
Mon Oct  4 00:59:59 1943 UT = Mon Oct  4 02:59:59 1943 CEST isdst=1 gmtoff=7200
Mon Oct  4 01:00:00 1943 UT = Mon Oct  4 02:00:00 1943 CET isdst=0 gmtoff=3600
Mon Apr  3 00:59:59 1944 UT = Mon Apr  3 01:59:59 1944 CET isdst=0 gmtoff=3600
Mon Apr  3 01:00:00 1944 UT = Mon Apr  3 03:00:00 1944 CEST isdst=1 gmtoff=7200
Mon Oct  2 00:59:59 1944 UT = Mon Oct  2 02:59:59 1944 CEST isdst=1 gmtoff=7200
Mon Oct  2 01:00:00 1944 UT = Mon Oct  2 02:00:00 1944 CET isdst=0 gmtoff=3600
Mon Apr  2 00:59:59 1945 UT = Mon Apr  2 01:59:59 1945 CET isdst=0 gmtoff=3600
Mon Apr  2 01:00:00 1945 UT = Mon Apr  2 03:00:00 1945 CEST isdst=1 gmtoff=7200
Mon Oct  1 00:59:59 1945 UT = Mon Oct  1 02:59:59 1945 CEST isdst=1 gmtoff=7200
Mon Oct  1 01:00:00 1945 UT = Mon Oct  1 02:00:00 1945 CET isdst=0 gmtoff=3600