Link the build-script-examples page in cargo::rustc-check-cfg

Author: Urgau

src/doc/src/reference/build-scripts.md

@@ -292,8 +292,13 @@ if foo_bar_condition {
 }
 ```
 
+For a more complete example see in the [build script examples][build-script-examples] page
+the [conditional compilation][conditional-compilation-example] example.
+
 [check-cfg-blog-post]: https://blog.rust-lang.org/2024/05/06/check-cfg.html
 [option-check-cfg]: ../../rustc/command-line-arguments.md#option-check-cfg
+[build-script-examples]: build-script-examples.md
+[conditional-compilation-example]: build-script-examples.md#conditional-compilation
 
 ### `cargo::rustc-env=VAR=VALUE` {#rustc-env}