Re: Core dumps in redisplay.

[Richard Stallman]

      /* Unblock input if we enter with input blocked.  This may happen if
         redisplay traps e.g. during tool-bar update with input blocked.  */
      while (INPUT_BLOCKED_P)
        UNBLOCK_INPUT;

      return Fthrow (Qtop_level, Qnil);
    }

    This approach of unblocking input appears completely useless to me,
    since unwinding the stack includes restoration of
    interrupt_input_blocked.

Probably that code was needed in the past,
before unwind_to_catch did this.  I will try deleting it.