Log Message:
snac: update to 2.68. Changes:

Fixed regression in link verification code (contributed by nowster).

Added ipv6 support for the https frontend connection (contributed
by hb9hnt).

New "Like by URL" operation (contributed by dheadshot).

Added support for a Mastodon-like `/share` link sharing URL, like the
one provided by sites like https://mastodonshare.com/ and such. To be
able to use it, you must reconfigure your https proxy to redirect
`/share` to snac (see `snac(8)`).

New linux landlock (sandboxing) support for enhanced security
(contributed by shtrophic). It's still a bit experimental, so you have
to enable it explicitly by recompiling with the WITH_LINUX_SANDBOX
directive (e.g. `make CFLAGS=-DWITH_LINUX_SANDBOX`).

Some search fixes regarding repeated matches.

The `export_csv` cmdline operation now exports the CSV files inside a
user's `export/` subdirectory instead of the current directory.

All CSV files to be imported must now be stored inside a user's
`import/` subdirectory instead of the current directory.

Mastodon API: more timeline paging tunings (contributed by nowster),
post language selected in apps is properly set.

The command-line operation `note` new reads the `LANG` environment
variable to set the post's language.

A new command-line operation, `note_unlisted`, allows posting "unlisted"
or "quiet public" posts.

The maximum number of entries in users' RSS feeds and in outboxes
can now be set via the `max_public_entries` variable in the
`server.json` file.

Fixed broken support for `Audio` objects.

Made xmpp and mailto URLs clickable.