Bring back LX zones.

*** 681,690 ****
--- 681,692 ----
  extern void overrun(), resvtrap();
  extern void _start(), cmnint();
  extern void achktrap(), mcetrap();
  extern void xmtrap();
  extern void fasttrap();
+ extern void sys_int80();
+ extern void brand_sys_int80();
  extern void dtrace_ret();
  
  #if !defined(__amd64)
  extern void pentium_pftrap();
  #endif