rustc_target: move in syntax::abi and flip dependency.

src/librustc_data_structures/Cargo.toml

@@ -11,6 +11,7 @@ crate-type = ["dylib"]
 [dependencies]
 ena = "0.9.1"
 log = "0.4"
+rustc_cratesio_shim = { path = "../librustc_cratesio_shim" }
 serialize = { path = "../libserialize" }
 cfg-if = "0.1.2"
 stable_deref_trait = "1.0.0"

src/librustc_data_structures/lib.rs

@@ -45,6 +45,10 @@ extern crate parking_lot;
 extern crate cfg_if;
 extern crate stable_deref_trait;
 
+// See librustc_cratesio_shim/Cargo.toml for a comment explaining this.
+#[allow(unused_extern_crates)]
+extern crate rustc_cratesio_shim;
+
 pub use rustc_serialize::hex::ToHex;
 
 pub mod array_vec;