remove unneeded extern crates from build tools

src/tools/build-manifest/Cargo.toml

@@ -7,4 +7,3 @@ edition = "2018"
 [dependencies]
 toml = "0.4"
 serde = { version = "1.0", features = ["derive"] }
-serde_derive = "1.0"

src/tools/compiletest/Cargo.toml

@@ -11,9 +11,8 @@ filetime = "0.2"
 getopts = "0.2"
 log = "0.4"
 regex = "1.0"
-serde = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-serde_derive = "1.0"
 rustfix = "0.4.1"
 lazy_static = "1.0"
 walkdir = "2"

src/tools/compiletest/src/errors.rs

@@ -7,6 +7,8 @@ use std::io::BufReader;
 use std::path::Path;
 use std::str::FromStr;
 
+use log::*;
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum ErrorKind {
     Help,

src/tools/compiletest/src/header.rs

@@ -4,6 +4,8 @@ use std::io::prelude::*;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
 
+use log::*;
+
 use crate::common::{self, CompareMode, Config, Mode};
 use crate::util;
 

src/tools/compiletest/src/json.rs

@@ -3,6 +3,7 @@
 
 use crate::errors::{Error, ErrorKind};
 use crate::runtest::ProcRes;
+use serde::Deserialize;
 use serde_json;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;

src/tools/compiletest/src/main.rs

@@ -3,14 +3,6 @@
 #![feature(vec_remove_item)]
 #![deny(warnings, rust_2018_idioms)]
 
-#[cfg(unix)]
-extern crate libc;
-#[macro_use]
-extern crate log;
-#[macro_use]
-extern crate lazy_static;
-#[macro_use]
-extern crate serde_derive;
 extern crate test;
 
 use crate::common::CompareMode;
@@ -30,6 +22,7 @@ use crate::util::logv;
 use walkdir::WalkDir;
 use env_logger;
 use getopts;
+use log::*;
 
 use self::header::{EarlyProps, Ignore};
 

src/tools/compiletest/src/runtest.rs

@@ -29,6 +29,9 @@ use std::path::{Path, PathBuf};
 use std::process::{Child, Command, ExitStatus, Output, Stdio};
 use std::str;
 
+use lazy_static::lazy_static;
+use log::*;
+
 use crate::extract_gdb_version;
 use crate::is_android_gdb_target;
 

src/tools/compiletest/src/util.rs

@@ -3,6 +3,8 @@ use std::env;
 use std::path::PathBuf;
 use crate::common::Config;
 
+use log::*;
+
 /// Conversion table from triple OS name to Rust SYSNAME
 const OS_TABLE: &'static [(&'static str, &'static str)] = &[
     ("android", "android"),

src/tools/tidy/Cargo.toml

@@ -6,6 +6,5 @@ edition = "2018"
 
 [dependencies]
 regex = "1"
-serde = "1.0.8"
-serde_derive = "1.0.8"
+serde = { version = "1.0.8", features = ["derive"] }
 serde_json = "1.0.2"

src/tools/tidy/src/deps.rs

@@ -5,7 +5,7 @@ use std::fs;
 use std::path::Path;
 use std::process::Command;
 
-use serde_derive::Deserialize;
+use serde::Deserialize;
 use serde_json;
 
 const LICENSES: &[&str] = &[