Document the minimal processor requirements

[nihil-admirari]

Got an issue about illegal instruction on a processor from 2010. Builds before 30 July 2024 were operational. Apparently support for older hardware was dropped since them, but what are the exact requirements?

[BtbN]

I'm not aware of any minimum processor requirements.
People have suggested optimizing for x86-64-v3, but I rejected that, so it really should work on any amd64 CPU as far as compiler options are concerned.
If an individual dependency decides to use more modern instructions unconditionally, that's sadly out of my control and also hard to track down.