plan9 linker: remove panics and improve 64 bit support

Don't @intCast when we do not need to, and change
some panics to unreachable when they can never happen.
f1aadfa77bJacob G-W committed on 7/8/2021, 9:12:08 PM· committed by Andrew Kelleyparentdb2d5b4
3 files changedLine totals unavailable