[tz] iana build failures on Windows

[Paul Eggert]

On 5/5/21 6:23 AM, Manuela Friedrich wrote:

> the new tracing seems to reveal a diff in the abbreviations.

Yes, that seems to be the problem. MS-Windows's struct tm does not have 
a tm_zone member; localtime merely puts time zone abbreviations into a 
global variable tzname, a la POSIX. On platforms lacking tm_zone, 
zdump's recently-changed code for remembering time zone abbreviations 
attempted to optimize localtime calls too aggressively and got the wrong 
abbreviation out of tzname.

I installed the attached patch into the development repository. It fixes 
things on Ubuntu when I compile with -DNO_TM_ZONE, which is how I 
reproduced the bug (NO_TM_ZONE tells zdump to pretend there's no tm_zone 
member). Please give it a try.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Fix-zdump-bug-on-TM_ZONE-platforms.patch
Type: text/x-patch
Size: 5506 bytes
Desc: not available
URL: <http://mm.icann.org/pipermail/tz/attachments/20210505/c07ae360/0001-Fix-zdump-bug-on-TM_ZONE-platforms.patch>