[tz] TZDB patches, UTF-8, and Microsoft Exchange

[Paul Eggert]

By the way, I had a little trouble applying your Greenland patch, 
because it was encoded in ISO 8859-1, and even though its email header 
line correctly said 'Content-Type: text/plain; charset="iso-8859-1"', 
Git understandably took alarm at the mixture of the patch's ISO 8859-1 
and tzdata's UTF-8 and refused to apply the patch.

As it turned out I needed to edit the patch anyway so this was only a 
minor hiccup. Still, it looks like this could be a systematic problem 
with Microsoft Outlook and/or Exchange, and I wonder whether we can 
briefly advise Microsoft-using patch-senders to avoid future glitches. 
Unfortunately I don't use Microsoft software for email and so don't know 
what to suggest.

Would it suffice to say "Please use 'git send-email'", or would that not 
work because Microsoft Exchange transcodes email from UTF-8 into ISO 8859-1?

Does Microsoft Exchange transcode attachments, so even "Please send the 
patch as an attachment" does not work?

Or was the problem here that Microsoft Outlook transcodes outgoing mail, 
and if so can this be fixed by asking users to specify UTF-8 encoding 
for outgoing messages at File > Options > Advanced > International 
options[1]?

Any suggestions would be welcome.

[1]: 
https://learn.microsoft.com/en-us/exchange/mail-flow/content-conversion/message-encoding?view=exchserver-2019#outlook-settings