Merge branch 'jn/eoie-ieot'

As the warning message shown by existing versions of Git for unknown index extensions is a bit too alarming, two new extensions are held back and not written by default for the upcoming release. * jn/eoie-ieot: index: make index.threads=true enable ieot and eoie ieot: default to not writing IEOT section eoie: default to not writing EOIE section