upgrading bind, openssl, openssh from source/srpms

I'm using RH7.2 (I assume it has trivial differences from 7.3, and the
7.2 list is silent for the last few months).

For bind, openssl, or other packages, are there any caveats when
building off a src.rpm from a newer redhat release?

I've managed to edit the spec file for bind 9.1.3 to accomidate 9.3.1.
 I'm using the current tarball from the isc.org site.  It stopped
building when I needed to update openssl.

I intend to build the package so the init script will have bind chroot
and drop privlidges (root -> bind) as it becomes a daemon. (like
trustix uses - I'll poke at their src.rpm for clues)

openssl still leaves me with questions.  What's the difference between
the 'engine' and non engine releases?  the openssl spec file said it
was using engine and a -usa suffix.  What's the significance of this? 
I assume I'll need the current engine release, right?

I'm building these on a stage box (semi-persistant vmware setup)
before I toss them at my colo.  Clearly, I want to avoid any support
requests on the system itself.  I don't have local access to it.

Thank you,


Scott Edwards
Daxal Communications - http://www.daxal.com/
Surf the USA - http://www.surfthe.us/