Log Message:
mail/squirrelmail: update to 1.4.23pre14977

Update to latest svn snapshot.  It includes various improvements for PHP 8
compatibility.  Address to PR pkg/57012.

Here are quote from commit log:

1.4.23pre14977 (2022-06-21)

* Add cookie SameSite attribute; uses default if "Strict" but can be
  overridden by $same_site_cookies in config_local.php
* Browser seems to respond better when deleting the cookie if you void its
  value also; helps actually get the cookie to be removed even though this
  feels more like a browser problem... maybe it does not like a date in
  1970?
* Make sure drafts are sent with the current date and not that of its
  previous 'Save Draft' action
* Add option to prefix new mail number to the front of the org title
  (browser title bar)
* Fix certain messages with headers in unknown charsets encoded as quoted
  printable showing up as blank sender/subject in message list
* Add ability for plugins to request additional header fields in the message
  list lookup
* Separate DNT and DSN
* Add proper RFC 3461 DSN functionality (previously we relied only on the
  Return-Receipt-To header)
* Cause message subject to show in page title when message view is loaded in
  its own window/tab
* Implement SQL identifier quoting in all cases
* Add option to folder prefs for marking deleted messages as read
* Fix: Login mechanisms other than "login" were broken if server returned
  untagged data before login response
* Greatly fix the plaintext display of messages that do not have a text
  part.
* Add ability to explicitly set prefs DB connection charset
* Add ability to explicitly set address book DB connection charset