🚀 go-pugleaf

The enclosed patch eliminates a gdb segfault.  The segfault occurred
during "info break" with a breakpoint whose condition is "this == 0".

*** ../gdb-3.2/expprint.c	Fri Jul  7 14:22:13 1989
--- expprint.c	Fri Aug  4 10:06:49 1989
***************
*** 276,282
  	    break;
  	  }
  
!     default:
        for (tem = 0; tem < sizeof op_print_tab / sizeof op_print_tab[0]; tem++)
  	if (op_print_tab[tem].opcode == opcode)
  	  {

--- 276,287 -----
  	    break;
  	  }
  
!     case OP_THIS:
!       ++(*pos);
!       fprintf (stream, "this");
!       return;
! 
!    default:
        for (tem = 0; tem < sizeof op_print_tab / sizeof op_print_tab[0]; tem++)
  	if (op_print_tab[tem].opcode == opcode)
  	  {