Compilation fails on OpenBSD

[oytunistrator]

An arrangement may be made for these operating systems. Some definitions are missing.

2 errors occurred:
--> openbsd/386 error: exit status 2
Stderr: # gopkg.in/src-d/go-git.v4
../../../../gopkg.in/src-d/go-git.v4/worktree_bsd.go:15:36: os.Atimespec undefined (type *syscall.Stat_t has no field or method Atimespec)

--> openbsd/amd64 error: exit status 2
Stderr: # gopkg.in/src-d/go-git.v4
../../../../gopkg.in/src-d/go-git.v4/worktree_bsd.go:15:36: os.Atimespec undefined (type *syscall.Stat_t has no field or method Atimespec)

[smola]

It might be Atim instead Atimespec for OpenBSD.

[mschoenlaub]

Is there a reason why atime is used in BSD but ctime on linux?

[mschoenlaub]

It might be Atim instead Atimespec for OpenBSD.

In fact, it differs between different BSD flavours apparently. See https://github.com/djherbis/times

[smola]

Is there a reason why atime is used in BSD but ctime on linux?

@mschoenlaub I have no idea. It seems reasonable that ctime was used on *BSD too. Also, using https://github.com/djherbis/times to solve this beyond OpenBSD looks sensible to me.

[smola]

Added hacktoberfest label, note that beyond fixing this build problem, tests should pass.