Add slice swap benchmark.

Adds a benchmark of various different ways of swapping the elements of
two slices, including several implementations in C.

Change-Id: I7ff490aefee6edfe5d7630b851278ce1fc385e8c
diff --git a/src/bindings.rs b/src/bindings.rs
new file mode 100644
index 0000000..ca24cc3
--- /dev/null
+++ b/src/bindings.rs
@@ -0,0 +1,6 @@
+#![allow(dead_code)]
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+
+include!(concat!(env!("OUT_DIR"), "/bindings.rs"));