Merge pull request #449 from Thomasdezeeuw/silence_spin_loop_warning

Allow use of deprecated atomic::spin_loop_hint

src/lib.rs

@@ -1362,6 +1362,8 @@ where
         }
         INITIALIZING => {
             while STATE.load(Ordering::SeqCst) == INITIALIZING {
+                // TODO: replace with `hint::spin_loop` once MSRV is 1.49.0.
+                #[allow(deprecated)]
                 std::sync::atomic::spin_loop_hint();
             }
             Err(SetLoggerError(()))