Remove SigevNotify on OpenBSD and Redox

Because nothing uses it on those OSes.

Author: asomers

CHANGELOG.md

@@ -76,6 +76,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - Removed a couple of termios constants on redox that were never actually
   supported.
   (#[1483](https://github.com/nix-rust/nix/pull/1483))
+
 - Removed `nix::sys::signal::NSIG`.  It was of dubious utility, and not correct
   for all platforms.
   (#[1484](https://github.com/nix-rust/nix/pull/1484))
@@ -87,6 +88,9 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 - Deprecated `SockAddr/InetAddr::to_str` in favor of `ToString::to_string`
   (#[1495](https://github.com/nix-rust/nix/pull/1495))
 
+- Removed `SigevNotify` on OpenBSD and Redox.
+  (#[1511](https://github.com/nix-rust/nix/pull/1511))
+
 ## [0.22.0] - 9 July 2021
 ### Added
 - Added `if_nameindex` (#[1445](https://github.com/nix-rust/nix/pull/1445))

src/sys/signal.rs

@@ -925,6 +925,7 @@ pub type type_of_thread_id = libc::pid_t;
 // sigval is actually a union of a int and a void*.  But it's never really used
 // as a pointer, because neither libc nor the kernel ever dereference it.  nix
 // therefore presents it as an intptr_t, which is how kevent uses it.
+#[cfg(not(any(target_os = "openbsd", target_os = "redox")))]
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub enum SigevNotify {
     /// No notification will be delivered