use a critical section instead

Sources/Mutex.swift

@@ -8,19 +8,46 @@
 
 import Foundation
 
+#if os(Windows)
+import WinSDK
+#endif
+
 final class Mutex: NSLocking {
-    
-    private var semaphore: DispatchSemaphore
+#if os(Windows)
+    private var mutex = CRITICAL_SECTION()
 
     init() {
-        semaphore = DispatchSemaphore(value: 1)
+        InitializeCriticalSection(&mutex)
+    }
+
+    deinit {
+        DeleteCriticalSection(&mutex)
     }
 
     func lock() {
-        semaphore.wait()
+        EnterCriticalSection(&mutex)
     }
 
     func unlock() {
-        semaphore.signal()
+        LeaveCriticalSection(&mutex)
     }
+#else
+    private var mutex = pthread_mutex_t()
+
+    init() {
+        pthread_mutex_init(&mutex, nil)
+    }
+
+    deinit {
+        pthread_mutex_destroy(&mutex)
+    }
+
+    func lock() {
+        pthread_mutex_lock(&mutex)
+    }
+
+    func unlock() {
+        pthread_mutex_unlock(&mutex)
+    }
+#endif
 }