error[E0428]: the name `fs_type_t` is defined multiple times
  --> /build/cargo-vendor-dir/nix-0.27.1/src/sys/statfs.rs:68:1
   |
66 | type fs_type_t = libc::c_uint;
   | ------------------------------ previous definition of the type `fs_type_t` here
67 | #[cfg(all(target_os = "linux", target_env = "musl"))]
68 | type fs_type_t = libc::c_ulong;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `fs_type_t` redefined here
   |
   = note: `fs_type_t` must be defined only once in the type namespace of this module

   Compiling rand v0.8.5
   Compiling proc-macro-error v1.0.4
   Compiling lazy_static v1.4.0
   Compiling overload v0.1.1
   Compiling rustix v0.38.34
   Compiling is_debug v1.0.1
   Compiling base64 v0.21.7
   Compiling const_format v0.2.32
   Compiling anstyle v1.0.2
   Compiling capnpc v0.19.0
error[E0592]: duplicate definitions with name `optimal_transfer_size`
   --> /build/cargo-vendor-dir/nix-0.27.1/src/sys/statfs.rs:348:5
    |
338 |     pub fn optimal_transfer_size(&self) -> u32 {
    |     ------------------------------------------ other definition for `optimal_transfer_size`
...
348 |     pub fn optimal_transfer_size(&self) -> libc::c_ulong {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ duplicate definitions for `optimal_transfer_size`

error[E0592]: duplicate definitions with name `block_size`
   --> /build/cargo-vendor-dir/nix-0.27.1/src/sys/statfs.rs:406:5
    |
398 |     pub fn block_size(&self) -> u32 {
    |     ------------------------------- other definition for `block_size`
...
406 |     pub fn block_size(&self) -> libc::c_ulong {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ duplicate definitions for `block_size`

error[E0592]: duplicate definitions with name `maximum_name_length`
   --> /build/cargo-vendor-dir/nix-0.27.1/src/sys/statfs.rs:497:5
    |
490 |     pub fn maximum_name_length(&self) -> u32 {
    |     ---------------------------------------- other definition for `maximum_name_length`
...
497 |     pub fn maximum_name_length(&self) -> libc::c_ulong {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ duplicate definitions for `maximum_name_length`

Some errors have detailed explanations: E0428, E0592.
For more information about an error, try `rustc --explain E0428`.
error: could not compile `nix` (lib) due to 4 previous errors
warning: build failed, waiting for other jobs to finish...