[MLton] Linker errors when building ADATE with amd64

[Florian Weimer]

* Lars Magnusson:

> We allocate a huge array of words (uint64_t[400000000]). Why this
> makes the linker fail I'm not sure, but I thought it was best to let
> you guys know.

amd64 uses 32-bit relocations by default.  If you have such a large
value in your data segment, parts of it will not be reachable by the
program.

I don't think there is a full 64 bit ABI for GNU/Linux.