auto merge of #14053 : FlaPer87/rust/master, r=huonw

This patch allows for using derivings for `kinds` in libcore

r? @alexcrichton

diff --combined src/libcore/lib.rs
index a771f30dfd197aabab3ea2d22c4d1304c9792b90,f32e87df5eccbb8294bfdd9a0524dcdc63ef2c09..38bce7a4741bf9ae7c38c969e2288f85255b625c
--- 1/src/libcore/lib.rs
--- 2/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@@ -106,11 -106,10 +106,12 @@@ mod should_not_exist
  mod std {
      pub use clone;
      pub use cmp;
+     pub use kinds;
  
      #[cfg(test)] pub use realstd::fmt;    // needed for fail!()
      #[cfg(test)] pub use realstd::rt;     // needed for fail!()
      #[cfg(test)] pub use realstd::option; // needed for assert!()
      #[cfg(test)] pub use realstd::os;     // needed for tests
 +    #[cfg(test)] pub use realstd::slice;  // needed for tests
 +    #[cfg(test)] pub use realstd::vec;    // needed for vec![]
  }