[MLton] x86_64 port status

[Stephen Weeks]

> >  struct PointerAux { unsigned char z[4]; } __attribute__ ((aligned (4)));
> >
> > This cut down the number of "cast increases required alignment" warnings
> > from 143 to 95.  All of the warnings eliminated were from basis/*
> > files.
> 
> Could you see if
> 
>    typedef unsigned char PointerAux __attribute__ ((aligned (4), may_alias));
>    typedef PointerAux* Pointer;
> 
> also suppresses the "cast increases required alignment" warnings?  I think 
> it is a little closer to our intentions.

Yes, that also suppresses the warnings outside of gc/*.c.  It also cut
the number of warnings down to 94, eliminating the only one left in the
basis part of the runtime.

  basis/Real/modf.c:10: warning: cast increases required alignment of target type

I don't understand why this warning is now gone.