Rename nix-bindings-bindgen-raw to nix-bindings-util-sys

Adopt idiomatic Rust `-sys` crate naming convention, aligning with
the direction in PR #37 without adopting the full crate splitting.

nix-bindings-expr/src/eval_state.rs

@@ -134,7 +134,6 @@ use anyhow::Context as _;
 use anyhow::{bail, Result};
 use cstr::cstr;
 use lazy_static::lazy_static;
-use nix_bindings_bindgen_raw as raw;
 use nix_bindings_store::path::StorePath;
 use nix_bindings_store::store::{Store, StoreWeak};
 use nix_bindings_util::context::Context;
@@ -142,6 +141,7 @@ use nix_bindings_util::string_return::{
     callback_get_result_string, callback_get_result_string_data,
 };
 use nix_bindings_util::{check_call, check_call_opt_key, result_string_init};
+use nix_bindings_util_sys as raw;
 use std::ffi::{c_char, CString};
 use std::iter::FromIterator;
 use std::os::raw::c_uint;

nix-bindings-expr/src/primop.rs

@@ -1,8 +1,8 @@
 use crate::eval_state::{EvalState, EvalStateWeak};
 use crate::value::Value;
 use anyhow::Result;
-use nix_bindings_bindgen_raw as raw;
 use nix_bindings_util::check_call;
+use nix_bindings_util_sys as raw;
 use std::ffi::{c_int, c_void, CStr, CString};
 use std::mem::ManuallyDrop;
 use std::ptr::{null, null_mut};

nix-bindings-expr/src/value.rs

@@ -1,7 +1,7 @@
 pub mod __private;
 
-use nix_bindings_bindgen_raw as raw;
 use nix_bindings_util::{check_call, context::Context};
+use nix_bindings_util_sys as raw;
 use std::ptr::{null_mut, NonNull};
 
 // TODO: test: cloning a thunk does not duplicate the evaluation.

nix-bindings-expr/src/value/__private.rs

@@ -1,6 +1,6 @@
 //! Functions that are relevant for other bindings modules, but normally not end users.
 use super::Value;
-use nix_bindings_bindgen_raw as raw;
+use nix_bindings_util_sys as raw;
 
 /// Take ownership of a new [`Value`].
 ///