Mine is currently “Off” and I have tons of “Call-time pass-by-reference” errors. The ~E_DEPRECATED option is not in the php.ini file comment on error handling and logging.
allow_call_time_pass_reference On will get rid of the deprecated warnings, but won’t really change functionality.
If we want to be compatible with php 5.4, we need to try and clean them up, http://www.php.net/manual/en/language.references.pass.php
But if folks are running 5.3 or earlier and have display_errors off, the warnings don’t change functionality, they just tell us that us a PHP language feature which is going away was used.
setting allow_call_time_pass_reference = On seems to have helped. The httpd/error_log is a much smaller file. I really ignored it for the longest time, but it was an annoyance. The /library/freeb/xmlrpcs.inc produced literally gigabytes of error messages.