bug#54844: 29.0.50; pgtk: with --daemon, DISPLAY gets set to "wayland-0"

[Sean Whitton]

In a terminal emulator where DISPLAY is ":0",

1. src/emacs --daemon -Q
2. lib-src/emacsclient -c
3. M-: (getenv "DISPLAY") RET

Value is "wayland-0" instead of ":0".  This is under Sway on Debian.
The problem does not occur if you launch without --daemon and then use
M-x server-start.

Seems similar to #53969.  I tried commenting out the only other Lisp
code which does (setenv "DISPLAY" ...) but that does not help.  So seems
like it is in C somewhere.

-- 
Sean Whitton