bug#70590: 29.3; PGTK emacs doesn't automatically run on the terminal when it has no graphical display

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 26 Apr 2024 11:25:40 +0100 (BST)
> From: Peter Oliver <lists.gnu.org@mavit.org.uk>
> 
> Traditionally, if you ran Emacs from a terminal, with no graphical display available, it used that terminal for its display.  With the pure GTK build of Emacs, this only works if you explicitly specify the –-no-window-system option.  Otherwise:
> 
> - - - - - - -
> $ env DISPLAY= WAYLAND_DISPLAY= emacs -Q
> 
> (emacs:13745): Gtk-WARNING **: 11:12:58.299: cannot open display: 
> $ echo $?
> 1
> - - - - - - -

See bug#63555.  We've decided not to fix this, given the royal mess
that GTK developers left behind, as described in the discussion of
that bug.  The NEWS file in the Emacs 29 distribution says, inter
alia, about the PGTK build:

  Note that, unlike the X build of Emacs, the PGTK build cannot
  automatically switch to text-mode interface (thus emulating '-nw') if
  it cannot determine the default display; it will instead complain and
  ask you to invoke it with the explicit '-nw' option.

Sorry.