eio

Merge pull request #822 from patricoferris/fiber-docs Fix docs for without_binding

Simplify custom "env" type in example Since we are already using the "constraint 'a =" syntax, the "as 'a" at the end is not needed, and even confusing.

Add missing_ok to Eio.Path.unlink (#828)

Make Linux and Posix eventfd functions configurable