[tz] need testing for new tzdb release for Brazil changes

[Paul Eggert]

On 5/27/19 1:48 PM, Paul Goyette wrote:
> Is the current rearguard format expected to live "forever"? 

No, the idea is only that it's rearguard "enough". That is, even the 
rearguard is on the march, and every announcement of the publication of 
the rearguard-format tarballs has said that they're intended to be 
temporary.

The next release (2019b, which should be reasonably soon) may be a good 
time to skip my publication of a rearguard-format tarball. The main use 
of the rearguard format seems to be last-minute updates for people using 
TZUpdater and the like, and we'll almost surely have a release 2019c 
before October anyway so people can update then. People who need 
rearguard format tarballs before then can make them by running "make 
rearguard_tarballs".