This question is quite common, there's probably some other posts somewhere in the forum, but I can't remember where.
Following powerpup118's answer, it's important for Raydium to have a consistent behavior for physics over the various platforms. It means a specific and "tested" release of ODE, with single precision. Most Linux distributions are providing unsuitable release of ODE (double precision, older/newer release) that can't be used "officially" for Raydium.
For instance, ManiaDrive is build around physics, so every single change in ODE may change the physics of the game, which is unacceptable for a game where players can compare scores online ...
It's the same story for PHP, where the "libphp" itself is not released everywhere (Debian, a few years ago at least, were not providing this package, only "static" release of php-cli, mod-php, ...) and with incompatible release and/or compilation options.
If it's a real trouble for you, it's quite easy to change the Makefile to make it using your own libraries. It seems to be how Fedora deals with Raydium and ManiaDrive for official packets, for instance. But I'll definitely not support something like that