Add spinlock dependency

Cargo.toml

@@ -8,6 +8,7 @@ crate-type = ["staticlib"]
 
 [dependencies]
 rlibc = "*"
+spin = "*"
 
 [dependencies.bitflags]
 git = "https://github.com/phil-opp/bitflags.git"

src/lib.rs

@@ -21,6 +21,7 @@ extern crate rlibc;
 extern crate multiboot2;
 #[macro_use]
 extern crate bitflags;
+extern crate spin;
 
 use core::fmt::Write;