MSRV 1.60: Conditionally import lazy.rs module (#472)

This simplifies lib.rs and allows for our testing code to be less
convoluted. Split out from #471. CC @briansmith

The MSRV for rand 0.9 is 1.61 and Debian stable is 1.63, so this is a
fine MSRV bump.

Signed-off-by: Joe Richey <joerichey@google.com>

Author: josephlr

.clippy.toml

@@ -1 +1 @@
-msrv = "1.57"
+msrv = "1.60"

.github/workflows/tests.yml

@@ -44,7 +44,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-22.04, windows-2022]
-        toolchain: [nightly, beta, stable, 1.57]
+        toolchain: [nightly, beta, stable, "1.60"]
         # Only Test macOS on stable to reduce macOS CI jobs
         include:
           # x86_64-apple-darwin.

Cargo.toml

@@ -2,7 +2,7 @@
 name = "getrandom"
 version = "0.2.15" # Also update html_root_url in lib.rs when bumping this
 edition = "2021"
-rust-version = "1.57" # Sync .clippy.toml, tests.yml, and README.md.
+rust-version = "1.60" # Sync .clippy.toml, tests.yml, and README.md.
 authors = ["The Rand Project Developers"]
 license = "MIT OR Apache-2.0"
 description = "A small cross-platform library for retrieving random data from system source"

README.md

@@ -52,7 +52,7 @@ crate features, WASM support and Custom RNGs see the
 
 ## Minimum Supported Rust Version
 
-This crate requires Rust 1.57.0 or later.
+This crate requires Rust 1.60.0 or later.
 
 ## Platform Support
 

src/lazy.rs

@@ -1,3 +1,5 @@
+//! Helpers built around pointer-sized atomics.
+#![cfg(target_has_atomic = "ptr")]
 #![allow(dead_code)]
 use core::{
     ffi::c_void,

src/lib.rs

@@ -216,6 +216,7 @@ use crate::util::{slice_as_uninit_mut, slice_assume_init_mut};
 use core::mem::MaybeUninit;
 
 mod error;
+mod lazy;
 mod util;
 // To prevent a breaking change when targets are added, we always export the
 // register_custom_getrandom macro, so old Custom RNG crates continue to build.
@@ -298,7 +299,6 @@ cfg_if! {
     ))] {
         mod util_libc;
         mod use_file;
-        mod lazy;
         mod linux_android;
         #[path = "linux_android_with_fallback.rs"] mod imp;
     } else if #[cfg(any(target_os = "android", target_os = "linux"))] {
@@ -309,7 +309,6 @@ cfg_if! {
         #[path = "solaris.rs"] mod imp;
     } else if #[cfg(target_os = "netbsd")] {
         mod util_libc;
-        mod lazy;
         #[path = "netbsd.rs"] mod imp;
     } else if #[cfg(target_os = "fuchsia")] {
         #[path = "fuchsia.rs"] mod imp;
@@ -331,11 +330,9 @@ cfg_if! {
     } else if #[cfg(windows)] {
         #[path = "windows.rs"] mod imp;
     } else if #[cfg(all(target_arch = "x86_64", target_env = "sgx"))] {
-        mod lazy;
         #[path = "rdrand.rs"] mod imp;
     } else if #[cfg(all(feature = "rdrand",
                         any(target_arch = "x86_64", target_arch = "x86")))] {
-        mod lazy;
         #[path = "rdrand.rs"] mod imp;
     } else if #[cfg(all(feature = "js",
                         any(target_arch = "wasm32", target_arch = "wasm64"),