Doesn't compile for Dragonfly or Illumos

[mholt]

GOOS=dragonfly go build returns an error:

github.com/hpcloud/tail/tail.go:191:20: undefined: OpenFile

This library is a dependency of quic-go which we use in Caddy and Caddy can no longer compile for Dragonfly because of this.

[mholt]

Same happens for GOOS=illumos :(

[mholt]

And for GOOS=solaris (yikes)

[nxadm]

@mholt, because this is an indirect dependency, the more sane way is just removing it upstream (I saw a PR is open).

However, I use this library in other projects so I decided to fork it because it looks it's abandoned for more than a year. I added the use of go modules and merged most of the open PRs (if they had a valid use case). You can find the repo here.