Update to work with the latest rust nightly (rustc 1.6.0-nightly (1727dee16 2015-11-26))

Author: fhartwig

regex_macros/src/lib.rs

@@ -20,6 +20,7 @@
 extern crate regex;
 extern crate syntax;
 extern crate rustc;
+extern crate rustc_plugin;
 
 use syntax::ast;
 use syntax::codemap;
@@ -30,7 +31,7 @@ use syntax::print::pprust;
 use syntax::fold::Folder;
 use syntax::ptr::P;
 
-use rustc::plugin::Registry;
+use rustc_plugin::Registry;
 
 use regex::Regex;
 use regex::internal::{