Add archive package

Archive package handles generating and applying diff tar streams
based on the OCI diff tar specification.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

archive/time_linux.go

@@ -0,0 +1,21 @@
+package archive
+
+import (
+	"time"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/pkg/errors"
+)
+
+func chtimes(path string, atime, mtime time.Time) error {
+	var utimes [2]unix.Timespec
+	utimes[0] = unix.NsecToTimespec(atime.UnixNano())
+	utimes[1] = unix.NsecToTimespec(mtime.UnixNano())
+
+	if err := unix.UtimesNanoAt(unix.AT_FDCWD, path, utimes[0:], unix.AT_SYMLINK_NOFOLLOW); err != nil {
+		return errors.Wrap(err, "failed call to UtimesNanoAt")
+	}
+
+	return nil
+}