Failed build on Windows even it is specifically not dependent

[AkinoKaede]

I know this package cannot support Windows. So I require it in Cargo.toml by:

[target.'cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd", target_os = "linux", target_os = "android"))'.dependencies]
sysctl = "0.5.5"

I think it's follow The Cargo Book.

But when I build on Windows, I got this error:

   Compiling sysctl v0.5.5
error[E0433]: failed to resolve: maybe a missing crate `sys`?
Error:   --> C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\sysctl-0.5.5\src\lib.rs:77:9
   |
77 | pub use sys::ctl::*;
   |         ^^^ maybe a missing crate `sys`?
   |
   = help: consider adding `extern crate sys` to use the `sys` crate

error[E0433]: failed to resolve: maybe a missing crate `sys`?
Error:   --> C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\sysctl-0.5.5\src\lib.rs:78:9
   |
78 | pub use sys::ctl_iter::*;
   |         ^^^ maybe a missing crate `sys`?
   |
   = help: consider adding `extern crate sys` to use the `sys` crate

error[E0432]: unresolved imports `sys::ctl::*`, `sys::ctl_iter::*`
Error:   --> C:\Users\runneradmin\.cargo\registry\src\index.crates.io-6f17d22bba15001f\sysctl-0.5.5\src\lib.rs:77:9
   |
77 | pub use sys::ctl::*;
   |         ^^^^^^^^^^^
78 | pub use sys::ctl_iter::*;
   |         ^^^^^^^^^^^^^^^^

Some errors have detailed explanations: E0432, E0433.
For more information about an error, try `rustc --explain E0432`.
error: could not compile `sysctl` (lib) due to 3 previous errors

It's seems a bug of Cargo, but it has not been solved for a long time.
rust-lang/cargo#10801

I think we should add some platform-specific conditional compilation before imports for workaround, like:

#[cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd",
    target_os = "linux", target_os = "android"))]
pub use sys::ctl::*;
pub use sys::ctl_iter::*;

[AkinoKaede]

My bad, I mistakenly added a dependency to a crate that didn't need systcl for all targets.

[orhun]

Just a comment, maybe using not(target_os = "windows") would be cleaner in your code.