[MLton] Progress on AMD64/FreeBSD

[Matthew Fluet]

Jesper Louis Andersen wrote:
> ok, new hypothesis:
> 
> printing the right size of the pointer gives
> 
> Couldn't map f7ff9954b0000000, 94208
> 
> etc. So I think this area is non-mappable for som reason. More 
> investigation
> needed.

It could be that FreeBSD just doesn't release the very high addresses 
for mmap'ing.  And it is just taking forever to work our way down to the 
available addresses.

We'll want to increase the scan stride for a 64-bit system.