Removing unused extern crates.

Author: elinorbgr

src/librustc_back/lib.rs

@@ -36,8 +36,6 @@
 #[phase(plugin, link)]
 extern crate log;
 extern crate syntax;
-extern crate libc;
-extern crate flate;
 extern crate serialize;
 
 pub mod abi;

src/libsyntax/diagnostic.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate libc;
-
 use codemap::{Pos, Span};
 use codemap;
 use diagnostics;