try using conditions for semaphores; standard semaphores are apparently too hard for OSX

stepmania/src/arch/Threads/Threads_Pthreads.h

@@ -53,6 +53,7 @@ private:
 	pthread_mutex_t mutex;
 };
 
+#if 0
 class SemaImpl_Pthreads: public SemaImpl
 {
 public:
@@ -66,6 +67,24 @@ public:
 private:
 	sem_t sem;
 };
+#else
+class SemaImpl_Pthreads: public SemaImpl
+{
+public:
+	SemaImpl_Pthreads( int iInitialValue );
+	~SemaImpl_Pthreads();
+	int GetValue() const { return m_iValue; }
+	void Post();
+	bool Wait();
+	bool TryWait();
+
+private:
+	pthread_cond_t m_Cond;
+	pthread_mutex_t m_Mutex;
+	unsigned m_iValue;
+};
+
+#endif
 
 #endif