I've improved the termux installation, adding an installer script to make
it easier, and fixing some issues that have been reported. And it supports
arm64 and also should work on Intel android devices. 
This feels very close to being able to remove the old deprecated Android
apps.

I'm temporarily running the arm64 builds on my phone, in a Debian chroot. But
it overheats, so this is a stopgap and it won't autobuild daily, only manually
at release time.

Released git-annex 6.20181011.

Today's work was sponsored by Jake Vosloo [on Patreon](http://patreon.com/joeyh/).
