Linux arm64 support

[Jim Jagielski]

Using the macOS and FreeBSD aarch64/arm64 work, I've been able to add support 
for Linux arm64/aarch64.

So far, just tested on Ubuntu24. I will look to see how far back we can go and 
maybe play around with Fedora.

--
Jim
  "This is an outrage!"
                        Tony Harrison