rwcancel: use unix.Poll again but bump x/sys so it uses ppoll under the hood

This reverts commit fcc601dbf0f6b626ec1d47a880cbe64f9c8fe385 but then
bumps go.mod.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

3 files changed, 2 insertions, 34 deletions

diff --git a/rwcancel/poll_linux.go b/rwcancel/poll_linux.go
deleted file mode 100644
index d9938c5..0000000
--- a/rwcancel/poll_linux.go
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
- */
-
-package rwcancel
-
-import "golang.org/x/sys/unix"
-
-func poll(fds []unix.PollFd, timeout int) (n int, err error) {
-	var ts *unix.Timespec
-	if timeout >= 0 {
-		ts = new(unix.Timespec)
-		*ts = unix.NsecToTimespec(int64(timeout) * 1e6)
-	}
-	return unix.Ppoll(fds, ts, nil)
-}
diff --git a/rwcancel/poll_unix.go b/rwcancel/poll_unix.go
deleted file mode 100644
index 37e9686..0000000
--- a/rwcancel/poll_unix.go
+++ /dev/null
@@ -1,15 +0,0 @@
-//go:build !windows && !linux
-// +build !windows,!linux
-
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
- */
-
-package rwcancel
-
-import "golang.org/x/sys/unix"
-
-func poll(fds []unix.PollFd, timeout int) (n int, err error) {
-	return unix.Poll(fds, timeout)
-}
diff --git a/rwcancel/rwcancel.go b/rwcancel/rwcancel.go
index 45cc73b..7013b16 100644
--- a/rwcancel/rwcancel.go
+++ b/rwcancel/rwcancel.go
@@ -49,7 +49,7 @@ func (rw *RWCancel) ReadyRead() bool {
 	pollFds := []unix.PollFd{{Fd: int32(rw.fd), Events: unix.POLLIN}, {Fd: closeFd, Events: unix.POLLIN}}
 	var err error
 	for {
-		_, err = poll(pollFds, -1)
+		_, err = unix.Poll(pollFds, -1)
 		if err == nil || !RetryAfterError(err) {
 			break
 		}
@@ -68,7 +68,7 @@ func (rw *RWCancel) ReadyWrite() bool {
 	pollFds := []unix.PollFd{{Fd: int32(rw.fd), Events: unix.POLLOUT}, {Fd: closeFd, Events: unix.POLLOUT}}
 	var err error
 	for {
-		_, err = poll(pollFds, -1)
+		_, err = unix.Poll(pollFds, -1)
 		if err == nil || !RetryAfterError(err) {
 			break
 		}