chcon/runcon: Only build on Linux

chcon/runcon rely on the selinux crate, that is empty on
non-Linux platforms.

This doesn't matter for normal builds that use the default features
for the platform (explicitly trying to build them will fail though).

This is a problem when using `cargo test --workspace` though,
as that tries to build all packages, including uu_chcon/uu_runcon.

Just prevent compilation of these source files when target_os != linux.

src/uu/chcon/src/chcon.rs

@@ -3,6 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 // spell-checker:ignore (vars) RFILE
+#![cfg(target_os = "linux")]
 #![allow(clippy::upper_case_acronyms)]
 
 use clap::builder::ValueParser;

src/uu/chcon/src/errors.rs

@@ -2,6 +2,8 @@
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
+#![cfg(target_os = "linux")]
+
 use std::ffi::OsString;
 use std::fmt::Write;
 use std::io;

src/uu/chcon/src/fts.rs

@@ -2,6 +2,8 @@
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
+#![cfg(target_os = "linux")]
+
 use std::ffi::{CStr, CString, OsStr};
 use std::marker::PhantomData;
 use std::os::raw::{c_int, c_long, c_short};

src/uu/chcon/src/main.rs

@@ -1 +1,2 @@
+#![cfg(target_os = "linux")]
 uucore::bin!(uu_chcon);

src/uu/runcon/src/errors.rs

@@ -2,6 +2,8 @@
 //
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
+#![cfg(target_os = "linux")]
+
 use std::ffi::OsString;
 use std::fmt::{Display, Formatter, Write};
 use std::io;

src/uu/runcon/src/main.rs

@@ -1 +1,2 @@
+#![cfg(target_os = "linux")]
 uucore::bin!(uu_runcon);

src/uu/runcon/src/runcon.rs

@@ -3,6 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 // spell-checker:ignore (vars) RFILE
+#![cfg(target_os = "linux")]
 
 use clap::builder::ValueParser;
 use uucore::error::{UClapError, UError, UResult};