[Toybox] Did I mention why I didn't implement out of tree build?

[Denys Nykula]

> The strange thing is that the binutils, gcc & musl lists don't seem to
> cause gmail to barf nearly as much as the toybox list does.

Mail-tester complains this way about this list server, rating its
likeliness of reaching destination as 32%:

> Listed in SORBS (last 28 days) http://www.sorbs.net/lookup.shtml
> Yellow listed in Hostkarma http://ipadmin.junkemailfilter.com/remove.php

> You may want to publish a DNS record (MX type) for the domain name lists.landley.net or use a different bounce email address.

> You do not have a DMARC record, please add a TXT record to your domain _dmarc.lists.landley.net with the following value: v=DMARC1; p=none

> [SPF] lists.landley.net does not allow your server
> to use toybox-bounces at lists.landley.net
> You do not have a SPF record, please add the following one to your domain lists.landley.net: v=spf1 a mx include:netblocks.dreamhost.com ~all

> Your message is not signed with DKIM

> Your message does not contain a List-Unsubscribe header

Had to sort all these out for clients' mailing lists before their mail
to major providers stopped breaking. Though it was more than a year
ago, providers might have more rules now than mail-tester knows of.

I also haven't seen any other mailing list sending its own additional
copy when a recipient is included in CC. So providers might consider
getting same letter twice weird, automatically blacklisting your
server when it repeatedly does that.