Improvements to path resolution in tlmgr and other scripts using kpathsea

[Karl Berry]

I trust you've actually tried these changes from SELFAUTOPARENT to
TEXMFROOT? They look ok to me, but SELFAUTOPARENT gets defined within
the kpsewhich/kpathsea code, while TEXMFROOT requires the texmf.cnf file.

Presumably you have kpsewhich set up in such a way that it can find
texmf.cnf (from its myriad builtin places to check), and then it should
all be fine, but ... something to be aware of. Sorry if already known.

At any rate, I don't think the changes will make any difference for native TL.
Norbert, feel free to apply when ready, or I can. --thanks, karl.