Migrate to serde-core

This should make compilation faster for downstream

src/de.rs

@@ -1,6 +1,8 @@
-use serde::Deserialize;
+use core::convert::TryInto;
 
-use serde::de::IntoDeserializer;
+use serde_core as serde;
+
+use serde::de::{self, Deserialize, DeserializeSeed, IntoDeserializer, Visitor};
 
 use super::error::{Error, Result};
 use crate::consts::*;
@@ -29,14 +31,6 @@ where
 
 ////////////////////////////////////////////////////////////////////////////////
 
-// TODO: remove these allowances again later
-// #![allow(unused_imports)]
-// #![allow(unused_variables)]
-
-use core::convert::TryInto;
-
-use serde::de::{self, DeserializeSeed, Visitor};
-
 /// A structure for deserializing a cbor-smol message.
 pub struct Deserializer<'de> {
     // This string starts with the input data and characters are truncated off

src/error.rs

@@ -1,6 +1,7 @@
 #![allow(unused_variables)]
 
 use core::fmt::{Display, Formatter};
+use serde_core as serde;
 
 /// This is the Result type used by cbor-smol.
 pub type Result<T, Err = Error> = core::result::Result<T, Err>;

src/lib.rs

@@ -4,6 +4,8 @@
 extern crate delog;
 generate_macros!();
 
+use serde_core as serde;
+
 pub(crate) mod consts;
 pub mod de;
 pub mod error;

src/ser.rs

@@ -1,6 +1,8 @@
 use super::error::{Error, Result};
-use serde::ser;
-use serde::Serialize;
+
+use serde_core as serde;
+
+use serde::ser::{self, Serialize};
 
 use core::mem;