Bug#1004666: Unable to set TEXMFAUXTREES in texlive

[Stewart Ferguson <Stew@sim-international.com>]

Package: texlive-latex-base
Version: 2020.20210202-3

I have a texmf tree that I plan to deploy in a *.deb package using a private
company-wide debian repository.

In postinst, I'm expecting to be able to add my tree to the TEXMFAUXTREES:

$ sudo tlmgr conf auxtrees add /usr/share/texlive/texmf-mycompany

Then I confirm it was added

$ tlmgr conf auxtrees
List of auxiliary texmf trees:
  /usr/share/texlive/texmf-mycompany

I can also confirm this in the texmf.cnf:

$ cat /usr/share/texlive/texmf.cnf 
TEXMFAUXTREES = /usr/share/texlive/texmf-mycompany,

However, it is not applied: 

$ kpsewhich -var-value TEXMFAUXTREES
{}

Further inspection shows /usr/share/texlive/texmf.cnf is not read by texlive: 

$ kpsewhich -all texmf.cnf
/etc/texmf/web2c/texmf.cnf
/usr/share/texmf/web2c/texmf.cnf
/usr/share/texlive/texmf-dist/web2c/texmf.cnf

$ kpsewhich -show-path texmf.cnf
/etc/texmf/web2c:/usr/local/share/texmf/web2c:/usr/share/texmf/web2c:/usr/share/texlive/texmf-dist/web2c://share/texmf/web2c

If support for /usr/share/texlive/texmf.cnf was removed to ensure tlmgr doesn't
conflict with apt, there should be an alternative provided so private package
maintainers can deploy trees.   

These are the texmf directories currently supported:
TEXMFLOCAL      /usr/local/share/texmf
TEXMFAUXTREES   {}
TEXMFDIST       /usr/share/texlive/texmf-dist
TEXMFHOME       $HOME/texmf