Supervisor compiles

Signed-off-by: John Howard <jhoward@microsoft.com>

supervisor/create_linux.go

@@ -0,0 +1,13 @@
+package supervisor
+
+import "github.com/docker/containerd/runtime"
+
+type platformStartTask struct {
+	Checkpoint *runtime.Checkpoint
+}
+
+func (task *startTask) setTaskCheckpoint(t *StartTask) {
+	if t.Checkpoint != nil {
+		task.Checkpoint = t.Checkpoint.Name
+	}
+}