$OpenBSD: patch-src_mutex_h,v 1.1 2017/04/30 08:56:45 espie Exp $
--- src/mutex.h.orig
+++ src/mutex.h
@@ -26,11 +26,15 @@
 /// A classical mutex.
 ///@note This implementation is per default recursive, so you can lock the mutex again
 ///      in the same thread where you already have locked it.
+struct SDL_mutex;
+class condvar;
+
+namespace dd {
 class mutex
 {
-	friend class condvar;
+	friend class ::condvar;
  protected:
-	struct SDL_mutex* mtx;
+	struct ::SDL_mutex* mtx;
  private:
 	mutex(const mutex& );
 	mutex& operator=(const mutex& );
@@ -47,9 +51,9 @@ class mutex
 	/// unlock the mutex
 	void unlock();
 };
+}
 
 
-
 /// A handy helper class for mutexes.
 ///@note Create a local object of that class and give it a mutex. It will lock the mutex
 ///	in its constructor and automatically unlock it in the destructor.
@@ -57,6 +61,7 @@ class mutex
 ///	inside the block or function that the object is declared in.
 class mutex_locker
 {
+	typedef dd::mutex mutex;
  protected:
 	mutex& mymutex;
  private:
