auto merge of #6500 : kud1ing/rust/cleanup, r=bstrie

Fixes #6445

diff --cc src/libsyntax/ext/base.rs
Simple merge

diff --cc src/libsyntax/ext/deriving/clone.rs
Simple merge

diff --cc src/libsyntax/ext/deriving/cmp/eq.rs
Simple merge

diff --cc src/libsyntax/ext/deriving/iter_bytes.rs
Simple merge