[tz] Portugal

[Paul Eggert]

Thanks for doing all that work. I assume your Portuguese is a lot better 
now than it was a few weeks ago!

I ran into one problem right away: "make DATAFORM=vanguard check" 
failed, with messages like this:

> ./zic -d check_now.dir tzdata.zi
> "tzdata.zi", line 3483: Zone continuation line end time is not after end time of previous line
> "tzdata.zi", line 3484: input line of unknown type
> "tzdata.zi", line 3485: input line of unknown type
> "tzdata.zi", line 3486: input line of unknown type

so it looks like some of the ifdeffed-ish lines need to be changed, in 
the vanguard section.

Some other comments, about the colonial data:

On 3/12/24 15:51, Tim Parenti via tz wrote:

> --- a/africa
> +++ b/africa
> @@ -105,11 +105,11 @@ Zone	Africa/Algiers	0:12:12 -	LMT	1891 Mar 16
>  #
>  # From Paul Eggert (2018-02-16):
>  # Shanks gives 1907 for the transition to +02.
> -# For now, ignore that and follow the 1911-05-26 Portuguese decree
> +# For now, ignore that and follow the 1911-05-24 Portuguese decree
>  # (see Europe/Lisbon).

I suggest rephrasing this Africa/Cape_Verde comment to something like 
"For timestamps before independence see commentary for Europe/Lisbon." 
We don't need to mention Shanks any more since we're no longer relying 
on Shanks for any of this data.

Likewise for Africa/Bissau and Africa/Luanda.

For Africa/Maputo, it seems that we should change the transition time to 
be the time you found, and ignore Shanks there as well. Although 
Wikipedia says Lourenço Marques (as Maputo was then called) starting in 
1904 had a tram service starting, which presumably had a need for 
reliable fixed GMT offset, it's possible that the tram service used one 
GMT offset while the local population typically used LMT. Given that 
Shanks was wrong so often everywhere else Portugal held sway, he's 
probably wrong here too.


>  # India
> -# From Paul Eggert (2014-08-11), after a heads-up from Stephen Colebourne:
> -# According to a Portuguese decree (1911-05-26)
> -# https://dre.pt/pdf1sdip/1911/05/12500/23132313.pdf
> -# Portuguese India switched to UT +05 on 1912-01-01.
> +# From Tim Parenti (2024-03-XXX), per Paul Eggert (2014-08-11), after a
> +# heads-up from Stephen Colebourne:
> +# According to a Portuguese decree (1911-05-24), Portuguese India switched to
> +# UT +05 on 1912-01-01 (see Europe/Lisbon).
>  #Zone	Asia/Panaji	[not enough info to complete]

Let's move this revised commentary to 'backzone' as it's unlikely we'll 
need to create an Asia/Panerji in the main data.