disabling unary "-" for unsigned types

[Walter Bright]

retard wrote:
> I'm really sorry I often sound so annoying. I guess I should stop posting 
> at all since there seems to be small value in criticizing things or 
> discussing various programming topics.

I did not intend to chase you away. You're welcome to stay here and 
criticize all you want.

What I'm trying to say is that there's far more value in contributing to 
the D project than there is in simply criticizing it. You have the 
knowledge and ability to, so why not?