Replace lazy_static! macro with once_cell

lazy_static! has fallen out of favor since better, non-macro ways of
accomplishing lazy init have been found.

rust-lang-nursery/lazy-static.rs#111

Author: dralley

Cargo.lock

@@ -17,4 +17,4 @@ proc-macro2 = "1.0"
 rustpython-compiler = { path = "../compiler", version = "0.1.1" }
 rustpython-bytecode = { path = "../bytecode", version = "0.1.1" }
 maplit = "1.0"
-lazy_static = "1"
+once_cell = "1.3.1"

derive/Cargo.toml

@@ -24,12 +24,11 @@ use std::fs;
 use std::path::{Path, PathBuf};
 use syn::parse::{Parse, ParseStream, Result as ParseResult};
 use syn::{self, parse2, Lit, LitByteStr, LitStr, Meta, Token};
+use once_cell::sync::Lazy;
 
-lazy_static::lazy_static! {
-    static ref CARGO_MANIFEST_DIR: PathBuf = PathBuf::from(
-        env::var_os("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR is not present"),
-    );
-}
+static CARGO_MANIFEST_DIR: Lazy<PathBuf> = Lazy::new(|| {
+    PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR is not present"))
+});
 
 enum CompilationSourceKind {
     File(PathBuf),

derive/src/compile_bytecode.rs

@@ -46,7 +46,7 @@ rustc_version_runtime = "0.1.*"
 statrs = "0.12.0"
 caseless = "0.2.1"
 chrono = { version = "=0.4.9", features = ["wasmbind"] }
-lazy_static = "^1.0.1"
+once_cell = "1.3.1"
 lexical = "4"
 itertools = "0.8"
 hex = "0.4.0"

vm/Cargo.toml

@@ -20,8 +20,6 @@ extern crate flamer;
 
 #[macro_use]
 extern crate bitflags;
-#[macro_use]
-extern crate lazy_static;
 extern crate lexical;
 #[macro_use]
 extern crate log;

vm/src/lib.rs

@@ -15,6 +15,7 @@ use std::sync::{Mutex, MutexGuard};
 use arr_macro::arr;
 use num_bigint::BigInt;
 use num_traits::ToPrimitive;
+use once_cell::sync::Lazy;
 #[cfg(feature = "rustpython-compiler")]
 use rustpython_compiler::{compile, error::CompileError};
 
@@ -1322,9 +1323,7 @@ impl Default for VirtualMachine {
     }
 }
 
-lazy_static! {
-    static ref REPR_GUARDS: Mutex<HashSet<usize>> = { Mutex::new(HashSet::new()) };
-}
+static REPR_GUARDS: Lazy<Mutex<HashSet<usize>>> = Lazy::new(|| Mutex::new(HashSet::new()));
 
 pub struct ReprGuard {
     id: usize,