Fix or remove 32-bit

[ray]

We have x86 support hacked in but is unsupported by Valve on this branch so doesn't have 100% compatibility.
This either needs a fix that lets us use fully compatible ABIs, or just drop support completely.

We can revisit this after we launch and collect some metrics.

[D-113CR]

To be fair, most computers made in the last 20 years have a 64-bit processor and operating system so dropping support for 32-bit shouldn't be a problem.