Linking with `kind=framework` is only supported when targeting macOS,
as frameworks are specific to that operating system.

Erroneous code example:

```ignore (should-compile_fail-but-cannot-doctest-conditionally-without-macos)
#[link(name = "FooCoreServices", kind = "framework")] extern {}
// OS used to compile is Linux for example
```

To solve this error you can use conditional compilation:

```
#[cfg_attr(target="macos", link(name = "FooCoreServices", kind = "framework"))]
extern {}
```

Learn more in the [Conditional Compilation][conditional-compilation] section
of the Reference.

[conditional-compilation]: https://doc.rust-lang.org/reference/attributes.html#conditional-compilation
