Like most iD titles, RTCW was ultimately released under the GPL, and is thus available as a GNU/Linux native game. Installing it under Gentoo is as simple as "emerge games-fps/rtcw", but unfortunately the game itself no longer works in modern GNU/Linux systems. This is only to be expected with proprietary software that becomes abandoned, and would affect the operation of that software on any OS, but naturally it doesn't have to be that way with Free Software, which can be revived at any time, even years later.
According to a poster with insider information, on the Pro Tools Forums:
It's my understanding that the most recent versions of OSX have departed from the Unix kernel heritage.
I have heard from a reliable source, inside Digidesign, that they actually have Protools running on Linux, and that the port from OSX isn't that hard, but are under contract obligation to Microsoft to not release a Linux port. Otherwise Microsoft can revoke their access to the Windows SDK.
Justice C. Bigler
House Sound Technician
Tulsa Performing Arts Center
I've been using Deepest Sender as my blogging tool up to now, but it always annoyed me that it didn't properly support Drupal categories (the actual category names are blank). Well finally here's a tool that does support categories in Drupal: