statfs: add namespace fs magic

Namespace filesystem magic is missing from FsType constants.

Author: tammela

CHANGELOG.md

@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ## [Unreleased] - ReleaseDate
 ### Added
 
+- Added `NSFS_MAGIC` FsType on Linux and Android.
+  ([#1829](https://github.com/nix-rust/nix/pull/1829))
 - Added `sched_getcpu` on platforms that support it.
   ([#1825](https://github.com/nix-rust/nix/pull/1825))
 - Added `sched_getaffinity` and `sched_setaffinity` on FreeBSD.

src/sys/statfs.rs

@@ -205,6 +205,9 @@ pub const USBDEVICE_SUPER_MAGIC: FsType = FsType(libc::USBDEVICE_SUPER_MAGIC as
 #[cfg(any(target_os = "linux", target_os = "android"))]
 #[allow(missing_docs)]
 pub const XENFS_SUPER_MAGIC: FsType = FsType(libc::XENFS_SUPER_MAGIC as fs_type_t);
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[allow(missing_docs)]
+pub const NSFS_MAGIC: FsType = FsType(libc::NSFS_MAGIC as fs_type_t);
 
 
 impl Statfs {