diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f1dcc4742..0ae60f45f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -156,7 +156,7 @@ jobs:
           #- i686-unknown-hurd-gnu
           # TODO: reenable <https://github.com/tokio-rs/mio/issues/1882>.
           #- powerpc64-ibm-aix
-          - riscv32imc-esp-espidf
+          #- riscv32imc-esp-espidf
           - sparcv9-sun-solaris
           - wasm32-wasip1
           - x86_64-apple-darwin
@@ -171,7 +171,7 @@ jobs:
           - x86_64-unknown-dragonfly
           - x86_64-unknown-freebsd
           - x86_64-unknown-fuchsia
-          - x86_64-unknown-haiku
+          #- x86_64-unknown-haiku
           - x86_64-unknown-hermit
           - x86_64-unknown-illumos
           - x86_64-unknown-linux-gnu
diff --git a/src/sys/shell/selector.rs b/src/sys/shell/selector.rs
index c7a1f8e6b..c31a7d360 100644
--- a/src/sys/shell/selector.rs
+++ b/src/sys/shell/selector.rs
@@ -40,7 +40,7 @@ cfg_os_ext! {
 }
 
 #[cfg(target_os = "wasi")]
-cfg_os_ext! {
+cfg_any_os_ext! {
     use crate::{Interest, Token};
 
     impl Selector {
diff --git a/src/sys/unix/selector/epoll.rs b/src/sys/unix/selector/epoll.rs
index 50dd9d4dc..9003d4423 100644
--- a/src/sys/unix/selector/epoll.rs
+++ b/src/sys/unix/selector/epoll.rs
@@ -82,7 +82,7 @@ impl Selector {
         syscall!(epoll_ctl(ep, libc::EPOLL_CTL_ADD, fd, &mut event)).map(|_| ())
     }
 
-    cfg_io_source! {
+    cfg_any_os_ext! {
     pub fn reregister(&self, fd: RawFd, token: Token, interests: Interest) -> io::Result<()> {
         let mut event = libc::epoll_event {
             events: interests_to_epoll(interests),
diff --git a/src/sys/unix/selector/kqueue.rs b/src/sys/unix/selector/kqueue.rs
index a22b69067..c3a40a564 100644
--- a/src/sys/unix/selector/kqueue.rs
+++ b/src/sys/unix/selector/kqueue.rs
@@ -1,20 +1,16 @@
 use std::mem;
+use std::mem::MaybeUninit;
 use std::ops::{Deref, DerefMut};
 use std::os::fd::{AsRawFd, FromRawFd, OwnedFd, RawFd};
+use std::slice;
 #[cfg(debug_assertions)]
 use std::sync::atomic::{AtomicUsize, Ordering};
 use std::time::Duration;
 use std::{cmp, io, ptr};
 
+use crate::Interest;
 use crate::Token;
 
-cfg_io_source! {
-    use std::mem::MaybeUninit;
-    use std::slice;
-
-    use crate::Interest;
-}
-
 /// Unique id for use as `SelectorId`.
 #[cfg(debug_assertions)]
 static NEXT_ID: AtomicUsize = AtomicUsize::new(1);
@@ -129,7 +125,7 @@ impl Selector {
         })
     }
 
-    cfg_io_source! {
+    #[cfg_attr(not(feature = "os-ext"), allow(dead_code))]
     pub fn register(&self, fd: RawFd, token: Token, interests: Interest) -> io::Result<()> {
         let flags = libc::EV_CLEAR | libc::EV_RECEIPT | libc::EV_ADD;
         // At most we need two changes, but maybe we only need 1.
@@ -169,6 +165,7 @@ impl Selector {
         kevent_register(self.kq.as_raw_fd(), changes, &[libc::EPIPE as i64])
     }
 
+    cfg_any_os_ext! {
     pub fn reregister(&self, fd: RawFd, token: Token, interests: Interest) -> io::Result<()> {
         let flags = libc::EV_CLEAR | libc::EV_RECEIPT;
         let write_flags = if interests.is_writable() {
@@ -275,7 +272,6 @@ impl Selector {
     }
 }
 
-cfg_io_source! {
 /// Register `changes` with `kq`ueue.
 fn kevent_register(
     kq: RawFd,
@@ -318,7 +314,6 @@ fn check_errors(events: &[libc::kevent], ignored_errors: &[i64]) -> io::Result<(
     }
     Ok(())
 }
-}
 
 cfg_io_source! {
     #[cfg(debug_assertions)]
diff --git a/src/sys/unix/selector/poll.rs b/src/sys/unix/selector/poll.rs
index 2ec9890df..bea421140 100644
--- a/src/sys/unix/selector/poll.rs
+++ b/src/sys/unix/selector/poll.rs
@@ -61,7 +61,7 @@ impl Selector {
         self.state.register_internal(fd, token, interests)
     }
 
-    cfg_io_source! {
+    cfg_any_os_ext! {
     pub fn reregister(&self, fd: RawFd, token: Token, interests: Interest) -> io::Result<()> {
         self.state.reregister(fd, token, interests)
     }
@@ -356,7 +356,7 @@ impl SelectorState {
         })
     }
 
-    cfg_io_source! {
+    cfg_any_os_ext! {
     pub fn reregister(&self, fd: RawFd, token: Token, interests: Interest) -> io::Result<()> {
         self.modify_fds(|fds| {
             let data = fds.fd_data.get_mut(&fd).ok_or(io::ErrorKind::NotFound)?;