I’m currently in the process of upgrading my old server to a nice new 64 bit CentOS 5 install and came across a few issues rebuilding some of the packages.
In general I try not to use customised versions of packages since it makes updating the machine so much easier when there’s nothing to rebuild, however some things I do customise slightly such as Apache and Exim.
Whilst rebuilding the Exim RPM I came across some strange errors which I assumed (correctly) were to do with the fact that it was a 64 bit OS not 32 bit.