Enable uconxtext module for s390x

Added to libc by rust-lang/libc@38569c7

Author: rtzoeller

CHANGELOG.md

@@ -45,6 +45,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
   (#[1563](https://github.com/nix-rust/nix/pull/1563))
 - Added `process_vm_readv` and `process_vm_writev` on Android.
   (#[1557](https://github.com/nix-rust/nix/pull/1557))
+- Added `nix::uncontext` module on s390x.
+  (#[1662](https://github.com/nix-rust/nix/pull/1662))
 
 ### Changed
 

src/lib.rs

@@ -146,7 +146,8 @@ feature! {
 // This can be implemented for other platforms as soon as libc
 // provides bindings for them.
 #[cfg(all(target_os = "linux",
-          any(target_arch = "x86", target_arch = "x86_64")))]
+          any(target_arch = "s390x", target_arch = "x86",
+              target_arch = "x86_64")))]
 feature! {
     #![feature = "ucontext"]
     #[allow(missing_docs)]