Move IDs into .ident
Use END(x)
Remove a.out support
Make CERROR hidden

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22280, verified by myself.

Change to use a register prefix.

Add a VAX version of __syscall. XXX Doesn't handle if syscall number is
> 0xffffffff or < -0xffffffff.