fix build for android

Author: devnexen

library/std/src/os/net/linux_ext/tcp.rs

@@ -4,6 +4,7 @@
 
 use crate::sealed::Sealed;
 use crate::sys_common::AsInner;
+#[cfg(target_os = "linux")]
 use crate::time::Duration;
 use crate::{io, net};