Merge pull request #8 from dtolnay/doc

Document extern crate link_cplusplus;

Author: dtolnay

README.md

@@ -24,7 +24,8 @@ neither of which are good experiences.
 ## Options
 
 An application or library that is fine with either of libstdc++ or libc++ being
-linked, whichever is the platform's default, should use:
+linked, whichever is the platform's default, should use the following in
+Cargo.toml:
 
 ```toml
 [dependencies]
@@ -50,6 +51,16 @@ flags from its build script can make this crate do nothing by using:
 link-cplusplus = { version = "1.0", features = ["nothing"] }
 ```
 
+Lastly, make sure to add an explicit `extern crate` dependency to your crate
+root, since the link-cplusplus crate will be otherwise unused and its link flags
+dropped.
+
+```rust
+// src/lib.rs
+
+extern crate link_cplusplus;
+```
+
 <br>
 
 #### License

src/lib.rs

@@ -26,7 +26,8 @@
 //! # Options
 //!
 //! An application or library that is fine with either of libstdc++ or libc++
-//! being linked, whichever is the platform's default, should use:
+//! being linked, whichever is the platform's default, should use the following
+//! in Cargo.toml:
 //!
 //! ```toml
 //! [dependencies]
@@ -51,3 +52,13 @@
 //! [dependencies]
 //! link-cplusplus = { version = "1.0", features = ["nothing"] }
 //! ```
+//!
+//! Lastly, make sure to add an explicit `extern crate` dependency to your crate
+//! root, since the link-cplusplus crate will be otherwise unused and its link
+//! flags dropped.
+//!
+//! ```
+//! // src/lib.rs
+//!
+//! extern crate link_cplusplus;
+//! ```