Try to depend only on the ir module being in scope.

Generated code should used qualified names assuming that `ir` is in
scope, not everything else.

lib/cretonne/src/ir/instructions.rs

@@ -10,6 +10,7 @@ use std::fmt::{self, Display, Formatter};
 use std::str::FromStr;
 use std::ops::{Deref, DerefMut};
 
+use ir;
 use ir::{Value, Type, Ebb, JumpTable, SigRef, FuncRef, StackSlot, MemFlags};
 use ir::immediates::{Imm64, Uimm8, Ieee32, Ieee64, Offset32, Uoffset32};
 use ir::condcodes::*;