Sorry, I must have been drunk while fixing the file. In texmf/web2c/texmf.cnf:
   TEXFORMATS    = .;$TEXMFOS/web2c/{$engine,}

I accidentally fixed TEXMFCNF instead of TEXFORMATS. Hopefully formats
won't fly to luatex/pdftex again. I'll fix.

IIRC, I was sitting next to you when you did that, so I must have been
drunk as well
hmm, should we promote a new prohibitionism era during TeX meeting ?
--
luigi