container: move scheduler policy constants to std

This avoids depending on cgo.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/container.go

@@ -40,7 +40,7 @@ type (
 		AllowOrphan bool
 		// Scheduling policy to set via sched_setscheduler(2). The zero value
 		// skips this call. Supported policies are [SCHED_BATCH], [SCHED_IDLE].
-		SchedPolicy SchedPolicy
+		SchedPolicy std.SchedPolicy
 		// Cgroup fd, nil to disable.
 		Cgroup *int
 		// ExtraFiles passed through to initial process in the container, with
@@ -373,7 +373,7 @@ func (p *Container) Start() error {
 
 			// sched_setscheduler: thread-directed but acts on all processes
 			// created from the calling thread
-			if p.SchedPolicy > 0 && p.SchedPolicy <= _SCHED_LAST {
+			if p.SchedPolicy > 0 && p.SchedPolicy <= std.SCHED_LAST {
 				var param schedParam
 				if priority, err := p.SchedPolicy.GetPriorityMin(); err != nil {
 					return &StartError{