stdlib: Inference engine caught some type errors! Also added some hot garbage.

stdlib/std/str.cl

@@ -1,5 +1,11 @@
 //! TODO: give conland a string type
-use super::num::u8;
+use super::num::{char, u8};
 
-// #[lang = "str"]
+#[lang = "str"]
 type str = [u8];
+
+#[builtin = "chars"]
+fn chars(s: &str) -> [char];
+
+#[builtin = "fmt"]
+fn fmt(..args) -> &str;