I've just installed Slackware 14.1 computer on an older computer that ran Debian without problems, so hardware is fine. Unfortunately having switched that machine it now has trouble with the nouveau driver. Mostly evident by lockups of Xorg coming out of suspend and often picking the wrong resolution on boot as also seen in the topic here here:

I'm trying the suggested solution from that topic of installing the proprietary nvidia driver. Unfortunately I get stuck on the fact that this machine is a multilib system. The latest nvidia-driver has a compat32 option in the slackbuild, but for the G73-based card in that machine I need to use the nvidia-legacy304 driver and there the compat32 option isn't present.

Looking through the slackbuild for the legacy304 itself I see no reference that it would perform a multilib install and the description explicitly states that multilib is not supported, see the slackbuild.

Hence the question: How can I actually install the nvidia-legacy304 driver on a multilib system?

Just download the driver from nvidia.com and run the installation script. The installer will ask you if you want to install the 32-bit compatibility libraries.

Edit: be sure to uninstall or at least blacklist nouveau. Eventually, use "nomodeset" as a kernel option in LILO. Oh, and switch to init 3 before building your driver.

I see that this could work, but was hoping that there would be a cleaner approach. This because just running the installer directly

1) bypasses the packaging system.
2) the nvidia installer typically overwrites several xorg files last time I tried making switching back to nouveau if this isn't the solution a pain.
3) the current slackbuild has a section in which it fixes wrong paths. Those fixes wouldn't happen without a proper slackbuild.

And to some extend my underlying worry is that the compatibility switch got removed on purpose from the slackbuild according to the changelog, which makes me think there was an explicit reason not to keep it in?

I use the 304 driver on one of my machines and it will automatically blacklist the nouveau driver and then you will have to reboot and start the install again. It does ask if you want to install the 32 bit compatibility drivers, but I don't usually run a multilib system. Other thaan that I haven't had any problems using the driver.