Inline cxx-symbols crate into cxx
The separation is no longer needed for Buck when linking with lld.
diff --git a/src/symbols/rust_vec.rs b/src/symbols/rust_vec.rs
index 7789454..fb49b40 100644
--- a/src/symbols/rust_vec.rs
+++ b/src/symbols/rust_vec.rs
@@ -1,12 +1,8 @@
use crate::rust_string::RustString;
+use crate::rust_vec::RustVec;
use std::mem;
use std::ptr;
-#[repr(C)]
-pub(crate) struct RustVec<T> {
- repr: Vec<T>,
-}
-
macro_rules! rust_vec_shims {
($segment:expr, $ty:ty) => {
const_assert_eq!(mem::size_of::<[usize; 3]>(), mem::size_of::<Vec<$ty>>());