bug#22975: 25.0.92; CANNOT_DUMP build can't start in tty mode

[Eli Zaretskii]

> From: Ken Raeburn <raeburn@raeburn.org>
> Date: Fri, 11 Mar 2016 06:17:45 -0500
> Cc: 22975@debbugs.gnu.org
> 
> It appears that Emacs tries to display the “Using load-path …” message, calls 
> echo_area_display, display_echo_area, with_echo_area_buffer, 
> display_echo_area_1, resize_mini_window, and grow_mini_window, which then uses
>   call3 (Qwindow_resize_root_window_vertically, …)
> but since we haven’t loaded window.el yet, there’s no function definition and 
> we raise a signal, quitting out of loadup and trying to display a message.

I'm not sure I follow: message calls message3_nolog, which should have
done this:

  void
  message3_nolog (Lisp_Object m)
  {
    struct frame *sf = SELECTED_FRAME ();

    if (FRAME_INITIAL_P (sf))
      message_to_stderr (m);

Is FRAME_INITIAL_P not doing it job in this case?

And just so I'm on the right page here: the "Loading foo..." messages
that loadup.el displays are shown where in this case? written to
stderr or displayed in the echo area?

> As to why normal temacs doesn’t show the problem: The load path displayed for 
> a normal temacs contains one directory, but for a CANNOT_DUMP emacs it 
> contains several; in my tests, resize_mini_window computed the height needed 
> as one line for the former and six lines for the latter, so only in the 
> latter case did grow_mini_window need to get called.

I think temacs should write these messages to stderr, so the whole
resize_mini_window rigmarole shouldn't get called at all.  What am I
missing?

> If I mess around with installation prefix length, window size, and font size, 
> I can get the CANNOT_DUMP emacs to start properly (but with unreadably tiny 
> characters); and if I make my terminal window quite narrow, I can get a 
> normal temacs to get into some kind of error loop (not the same failure mode 
> but probably a similar root cause). So it’s not just the CANNOT_DUMP setting 
> that’s causing the problem.

Error loop that displays what messages?