mostly 64 bit support.

mostly 64 bit support.

- fixed a number of places where we tried to allocate 64bit
  regs. added honeypot in regalloc to catch these in the future.
- implemented quad copying in sgen
- cgen64.c, add, mul
- clearfat done
- D_REGREG output from 5g (linker already knew about them)
- gmove done
- optoas almost done, last bit probably not needed
- D_SHIFT support in list.c

R=rsc
APPROVED=rsc
DELTA=963  (711 added, 112 deleted, 140 changed)
OCL=33619
CL=33688