Fails to properly decode slim tzdata

[Milan Crha]

On Mon, 2021-03-15 at 09:34 -0400, Ken Murchison wrote:
> > Hmm.  I get the following on my branch:
> > 
> > 
> >  *** Summary: 424 zones tested, 0 days failed, 154760 okay => 0% 
> > failed ***
> > 
> 
> What are you compile options?

	Hi,
I build the tzdata myself, from the sources at:
https://github.com/eggert/tz

The build options for libical I use are:

   -DGOBJECT_INTROSPECTION=ON
   -DUSE_BUILTIN_TZDATA=OFF
   -DICAL_BUILD_DOCS=ON
   -DADDRESS_SANITIZER=OFF
   -DTHREAD_SANITIZER=OFF
   -DICAL_GLIB_VAPI=ON

When I build the master branch on a Fedora Rawhide, which has
tzdata-2021a-1.fc34.noarch, then with your patch I also get 0 failed
days. Maybe the master branch contains some other fixes, which are not
part of the 3.0 branch? I see some line offset claims when I apply the
patch there.

I tried the master branch on my main machine and it still claims some
failures. Hmm, thinking of it, I do not install the tzdata into the
system prefix, thus the system routines do not use the same tzdata as
libical, which can be the reason why it fails here, but not on the
Fedora Rawhide, where I use the system tzada (in the fat format).

Hope it helps.

	Bye,
	Milan