chroot function availability disqualifiers

Hello everyone, As a bit of proactive documentation, I'm trying to determine exactly what the disqualifying conditions are for chroot's availability in PHP. So far as I can tell, from ext/standard/dir.c, chroot is only compiled in #if defined(HAVE_CHROOT) && !defined(ZTS) && ENABLE_CHROOT_FUNC HAVE_CHROOT seems to always be set to 1 by php_config.h, so far as I can tell. ZTS, as I understand it, indicates whether PHP is being compiled threadsafe, and ENABLE_CHROOT_FUNC seems to be related to the deprecated(?) --enable-chroot-func switch. Could someone with a better understanding of the compile process illuminate me as to all of the reasons why chroot might not be available? Thanks, Justin Martin, a.k.a. FrozenFire