Okay, for anyone else looking for this, here you go.
To install the Mach64 driver on VectorLinux (5.9 at least):
If you didn't install the dev and/or kernel source packages during install, do the following as root:
slapt-get --install binutils make gcc kernel-src
cd /usr/src/linux-`uname -r`/include
ln -s asm-<your architecture> asm (e.g. ln -s asm-i386 asm)
Continuing as root:
slapt-get --install git
cd ~ (or some other working directory)
git clone git://anongit.freedesktop.org/git/mesa/drm
cp *.ko /lib/modules/`uname -r`/kernel/drivers/char/drm/
To clean up unneeded stuff:
slapt-get --remove binutils make kernel-src git
cd ~ (or whatever working directory you used above)
rm -r drm/
That's it. Make sure your system is set to 16-bit color for best performance. E.g. in your /etc/X11/xorg.conf file:
Identifier "Default Screen"
Monitor "Configured Monitor"
Device "Configured Video Device"
Apparently my system doesn't support blending, as I get "illegal instruction" on the console when an application tries to use it. So if you see this problem, disable that when you start an application (e.g. chromium -nb)