Only pull in PidfdReaper if feature rt is enabled on Linux

Instead of automatically enabling feature `rt` if `process` is enabled,
even if the target os is not `linux`.

Signed-off-by: Jiahao XU <[email protected]>

tokio/Cargo.toml

@@ -59,7 +59,6 @@ net = [
  "windows-sys/Win32_System_SystemServices",
 ]
 process = [
- "rt",
  "bytes",
  "libc",
  "mio/os-poll",

tokio/src/process/unix/mod.rs

@@ -27,7 +27,7 @@ use orphan::{OrphanQueue, OrphanQueueImpl, Wait};
 mod reap;
 use reap::Reaper;
 
-#[cfg(target_os = "linux")]
+#[cfg(all(target_os = "linux", feature = "rt"))]
 mod pidfd_reaper;
 
 use crate::io::{AsyncRead, AsyncWrite, PollEvented, ReadBuf};
@@ -105,7 +105,7 @@ impl OrphanQueue<StdChild> for GlobalOrphanQueue {
 #[must_use = "futures do nothing unless polled"]
 pub(crate) enum Child {
  SignalReaper(Reaper<StdChild, GlobalOrphanQueue, Signal>),
- #[cfg(target_os = "linux")]
+ #[cfg(all(target_os = "linux", feature = "rt"))]
  PidfdReaper(pidfd_reaper::PidfdReaper<StdChild, GlobalOrphanQueue>),
 }
 
@@ -121,7 +121,7 @@ pub(crate) fn spawn_child(cmd: &mut std::process::Command) -> io::Result<Spawned
  let stdout = child.stdout.take().map(stdio).transpose()?;
  let stderr = child.stderr.take().map(stdio).transpose()?;
 
- #[cfg(target_os = "linux")]
+ #[cfg(all(target_os = "linux", feature = "rt"))]
  match pidfd_reaper::PidfdReaper::new(child, GlobalOrphanQueue) {
  Ok(pidfd_reaper) => {
  return Ok(SpawnedChild {
@@ -149,15 +149,15 @@ impl Child {
  pub(crate) fn id(&self) -> u32 {
  match self {
  Self::SignalReaper(signal_reaper) => signal_reaper.id(),
- #[cfg(target_os = "linux")]
+ #[cfg(all(target_os = "linux", feature = "rt"))]
  Self::PidfdReaper(pidfd_reaper) => pidfd_reaper.id(),
  }
  }
 
  fn std_child(&mut self) -> &mut StdChild {
  match self {
  Self::SignalReaper(signal_reaper) => signal_reaper.inner_mut(),
- #[cfg(target_os = "linux")]
+ #[cfg(all(target_os = "linux", feature = "rt"))]
  Self::PidfdReaper(pidfd_reaper) => pidfd_reaper.inner_mut(),
  }
  }
@@ -179,7 +179,7 @@ impl Future for Child {
  fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
  match Pin::into_inner(self) {
  Self::SignalReaper(signal_reaper) => Pin::new(signal_reaper).poll(cx),
- #[cfg(target_os = "linux")]
+ #[cfg(all(target_os = "linux", feature = "rt"))]
  Self::PidfdReaper(pidfd_reaper) => Pin::new(pidfd_reaper).poll(cx),
  }
  }