Fix README example

README.md

@@ -10,10 +10,8 @@ order to build a set of C files into a static archive.
 ```rust,no_run
 extern crate gcc;
 
-use std::default::Default;
-
 fn main() {
-    gcc::compile_library("libfoo.a", &Default::default(), &["foo.c", "bar.c"]);
+    gcc::compile_library("libfoo.a", &["foo.c", "bar.c"]);
 }
 ```