Linearize cycle dependency between cxx crate and cxx.cc
diff --git a/src/symbols/rust_vec.rs b/src/symbols/rust_vec.rs
index 163f7a9..7789454 100644
--- a/src/symbols/rust_vec.rs
+++ b/src/symbols/rust_vec.rs
@@ -1,4 +1,4 @@
-use super::rust_string::RustString;
+use crate::rust_string::RustString;
 use std::mem;
 use std::ptr;