modify #[deriving(Eq)] to emit #[structural_match]

to careful use of the span from deriving, we
can permit it in stable code if it derives from
deriving (not-even-a-pun intended)

src/libsyntax_ext/lib.rs

@@ -24,6 +24,7 @@
 #![feature(str_char)]
 
 extern crate fmt_macros;
+#[macro_use] extern crate log;
 #[macro_use]
 extern crate syntax;