Define MntFlags and unmount on all of the BSDs.

CHANGELOG.md

@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ## [Unreleased] - ReleaseDate
 ### Added
 
+- Add `MntFlags` and `unmount` on all of the BSDs.
+  ([#1849](https://github.com/nix-rust/nix/pull/1849))
 - Added a 'Statfs::flags' method.
   ([#1849](https://github.com/nix-rust/nix/pull/1849))
 - Added `NSFS_MAGIC` FsType on Linux and Android.

src/lib.rs

@@ -106,7 +106,6 @@ feature! {
     #[allow(missing_docs)]
     pub mod kmod;
 }
-#[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
 feature! {
     #![feature = "mount"]
     pub mod mount;

src/mount/bsd.rs

@@ -1,16 +1,22 @@
+#[cfg(target_os = "freebsd")]
 use crate::{
     Error,
+};
+use crate::{
     Errno,
     NixPath,
     Result,
 };
-use libc::{c_char, c_int, c_uint, c_void};
+#[cfg(target_os = "freebsd")]
+use libc::{c_char, c_uint, c_void};
+use libc::c_int;
+#[cfg(target_os = "freebsd")]
 use std::{
     borrow::Cow,
     ffi::{CString, CStr},
+    marker::PhantomData,
     fmt,
     io,
-    marker::PhantomData,
 };
 
 
@@ -110,12 +116,14 @@ libc_bitflags!(
 ///
 /// It wraps an [`Errno`], but also may contain an additional message returned
 /// by `nmount(2)`.
+#[cfg(target_os = "freebsd")]
 #[derive(Debug)]
 pub struct NmountError {
     errno: Error,
     errmsg: Option<String>
 }
 
+#[cfg(target_os = "freebsd")]
 impl NmountError {
     /// Returns the additional error string sometimes generated by `nmount(2)`.
     pub fn errmsg(&self) -> Option<&str> {
@@ -135,8 +143,10 @@ impl NmountError {
     }
 }
 
+#[cfg(target_os = "freebsd")]
 impl std::error::Error for NmountError {}
 
+#[cfg(target_os = "freebsd")]
 impl fmt::Display for NmountError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         if let Some(errmsg) = &self.errmsg {
@@ -147,13 +157,15 @@ impl fmt::Display for NmountError {
     }
 }
 
+#[cfg(target_os = "freebsd")]
 impl From<NmountError> for io::Error {
     fn from(err: NmountError) -> Self {
         err.errno.into()
     }
 }
 
 /// Result type of [`Nmount::nmount`].
+#[cfg(target_os = "freebsd")]
 pub type NmountResult = std::result::Result<(), NmountError>;
 
 /// Mount a FreeBSD file system.