Repairing BigInt const

[Matthias Walter]

Hi all,

as it seems, the current version of BigInt is not capable of const, i.e.
BigInt(1) + const(BigInt)(1) does not work.

Is there already an effort to fix this or would it make sense if I had
taken some time to create a fix for it? I have no idea of all the asm in
the x86 specialization but as const is an interface thing, I should be
able to figure out everything without that knowledge. Or are there
general design problems, such that this would be a waste of time?

Matthias