Hi,
I installed texlive package per package (not using the "texlive")
package.  I end up not being able to launch any of pdflatex, lualatex
nor xelatex, as I obtain

Can't locate mktexlsr.pl in @INC (@INC contains: /gnu/store/tlpkg /gnu/store/texmf-dist/scripts/texlive /home/gabriel/.
guix-profile/share/texmf-dist/scripts/texlive/ /gnu/store/dna8kpb00kq176rz8x69yy4j33my2q55-perl-5.28.0/lib/perl5/site_p
erl/5.28.0/x86_64-linux-thread-multi /gnu/store/dna8kpb00kq176rz8x69yy4j33my2q55-perl-5.28.0/lib/perl5/site_perl/5.28.0
 /gnu/store/dna8kpb00kq176rz8x69yy4j33my2q55-perl-5.28.0/lib/perl5/5.28.0/x86_64-linux-thread-multi /gnu/store/dna8kpb0
0kq176rz8x69yy4j33my2q55-perl-5.28.0/lib/perl5/5.28.0) at /home/gabriel/.guix-profile/bin/mktexfmt line 23.           
BEGIN failed--compilation aborted at /home/gabriel/.guix-profile/bin/mktexfmt line 25.
I can't find the format file `lualatex.fmt'!

The content '/gnu/store/{tlpkg,texmf-dist}' look suspicious.  Inspecting
mktexfmt, we learn that those paths are returned by 'kpsewhich
-var-value=TEXMFROOT'.  How can we change the path returned by
kpsewhich?

Cheers,
Gabriel