This should help with the bootstrapping of non-emulated environment.
For example, I have a problem with the RC2014: I can't send it
bootstrap info until the ACIA is up. I need to find a way...
Doing this was a bit stupid. These offsets are constants. Moreover,
having them in stable ABI had us construct the boot binary from the
stable ABI of the host, making it very difficult to change RAMSTART
for a new system.