Clean up before patch submission

* src/lisp.h (struct handler): Remove unused 'bytecode_offset' field,
which was added at some point while prototyping.

* src/bytecode.c (UPDATE_OFFSET): Subtract 1, so the offset is accurate.

src/bytecode.c

@@ -313,7 +313,7 @@ enum byte_code_op
 
 /* Update the thread's bytecode offset, just before NEXT. */
 
-#define UPDATE_OFFSET (backtrace_byte_offset = pc - bytestr_data)
+#define UPDATE_OFFSET (backtrace_byte_offset = pc - bytestr_data - 1)
 
 DEFUN ("byte-code", Fbyte_code, Sbyte_code, 3, 3, 0,
        doc: /* Function used internally in byte-compiled code.

src/eval.c

@@ -342,7 +342,9 @@ call_debugger (Lisp_Object arg)
 	 redisplay, which necessarily leads to display problems.  */
   specbind (Qinhibit_eval_during_redisplay, Qt);
 #endif
+
   val = apply1 (Vdebugger, arg);
+
   /* Interrupting redisplay and resuming it later is not safe under
      all circumstances.  So, when the debugger returns, abort the
      interrupted redisplay by going back to the top-level.  */

src/lisp.h

@@ -3281,9 +3281,6 @@ struct handler
   enum nonlocal_exit nonlocal_exit;
   Lisp_Object val;
 
-  /* The bytecode offset where the error occurred. */
-  int bytecode_offset;
-
   struct handler *next;
   struct handler *nextfree;