compiler support added for precise GC

[Walter Bright]

On 4/15/2012 7:24 PM, Walter Bright wrote:
> 3. Many types will follow similar patterns:
>
> ptr .. int .. ptr .. int
>
> ptr .. ptr
>
> int .. ptr
>
> I suggest that specializations exist for these to avoid generating innumerable
> identical data structures or functions. In fact, if they are named with names like:
> scanpipi()
> scanpp()
> scanip()
>
> then the linker will automatically remove duplicates.

I realized after I posted this that the patterns:

ptr .. int .. ptr .. int
ptr .. int .. ptr
ptr .. int .. ptr .. int .. int

are the same as far as marking goes, and so should all generate the same 
function/data.