[Lightning] stuff to do for x86-64

[Paolo Bonzini]

x86 works now, and all archs but x86-64 passes make distcheck.

mzscheme guys, i think you can start like this:

- get the branch with arch (or ask me to send a copy)
- copy *-common.h and i386/*.h into the lightning/i386 folder of 
mzscheme (except funcs.h, i saw you modified it)
- make an asm.h like this

#include "asm-i386.h"
#ifdef JIT_X86_64
#include "asm-32.h"
#else
#include "asm-64.h"
#endif

and likewise for core.h

- make it compile; failures imply that you had patched something else 
and I have not merged/decided whether to merge that change.  but it 
should be relatively limited scope.

- test it and send patches :-) (i'll take care of modifying the patches 
to account for your modifications to the original GNU lightning code).


on the other hand, for me the todo list is:

* test non-distribution mode (i.e. if GNU Smalltalk compiles and passes 
make distcheck)

* test gnu smalltalk (i.e. bugs should be ironed out)

then we can merge into mainline (same features, plus incomplete x86-64 
back-end)

* test x86-64 / complete back-end (machines and patches are welcome)

* add SSE back-end for math (should be same for i386 too, so I can do 
it, but don't hold your breath)

Paolo