How to initialize environment variables on Wayland and elogind

[YOSHINO Yoshihito]

Hi,

I am looking for a way to initialize environment variables on Wayland
and elogind,
like GTK_IM_MODULE for an input method system.

Xorg session sources shell scripts through /etc/X11/Xsession.d/ .
Wayland itself does not use any such files, so the variables are not set at all.

Since GNOME Wayland + gdm3 + systemd-logind is the default desktop in Buster,
I am first sruggling with the combination.
systemd-logind >= 233 seems to run any program found in
/usr/lib/systemd/user-environment-generators/, which echoes ENVKEY=VAL to stdout
that the program wants to define to the activation environment of a
new systemd ---user
session, and gdm3 import variables in the activation environment to
the environment
of the new desktop session. I am currently considering the use of the
user-environment-generators, like done in some variables of gnupg2 (#855868).

elogind does not seem to (and will probably not) have
user-environment-generators.
Any suggestions?

Thanks,
-- 
YOSHINO Yoshihito <yy.y.ja.jp at gmail.com>