Apache 2.2 and php 5.4.5 failing on freebsd 8.3

[John Levine]

I have a fully patche amd64 freebsd 8.3 server with apache 2.2 and PHP 5.4.5.

In the past day, php scripts have started failing with a variety of random errors,
they hang, errors claiming that builtins like require_once() are not found, and
other stuff.  I don't see any pattern.  I also can't figure out what's changed.
I update the ports fairly often, but none of the recent updates were for apache
or PHP.

I've done all the usual voodoo repair: I have rebuilt apache, php, and
all the php modules from source, and rebooted, and it didn't help.

Does this sound familiar?  Any suggestions beyond what I've already done?

R's,
John