Setting environment variables (GUIX on foreign distro)

[Zelphir Kaltstahl]

Hello,

My question regards setting environment variables, which are considered
by applications installed via GUIX on a foreign distro (Trisquel). What
is the best practice to set custom environment variables?

I've successfully set them in my ~/.guix-profile/etc/profile before, but
there they will be overwritten when I update packages. I could not find
anything about an extra file with the purpose of housing user
definitions and not changing them.

My scenario is, that I wish to point LyX to a non-GUIX-installed texlive
distribution, which is done by setting the following environment variables:

TEXMF, TEXMFCNF

My texlive installation is more up to date than the one in GUIX
packages, complete and I wish to use that one, instead of having GUIX
point to any texlive distribution of GUIX.

Regards,
Zelphir