add EventImpl::WaitTimeoutSupported

stepmania/src/arch/Threads/Threads.h

@@ -49,6 +49,7 @@ public:
 	virtual bool Wait( RageTimer *pTimeout ) = 0;
 	virtual void Signal() = 0;
 	virtual void Broadcast() = 0;
+	virtual bool WaitTimeoutSupported() const = 0;
 };
 
 class SemaImpl

stepmania/src/arch/Threads/Threads_Pthreads.cpp

@@ -348,12 +348,22 @@ bool EventImpl_Pthreads::Wait( RageTimer *pTimeout )
 	int iRet = pthread_cond_timedwait( &m_Cond, &m_pParent->mutex, &abstime );
 	return iRet != ETIMEDOUT;
 }
+
+bool EventImpl_Pthreads::WaitTimeoutSupported() const
+{
+	return true;
+}
 #else
 bool EventImpl_Pthreads::Wait( RageTimer *pTimeout )
 {
 	pthread_cond_wait( &m_Cond, &m_pParent->mutex );
 	return true;
 }
+
+bool EventImpl_Pthreads::WaitTimeoutSupported() const
+{
+	return false;
+}
 #endif
 
 void EventImpl_Pthreads::Signal()

stepmania/src/arch/Threads/Threads_Pthreads.h

@@ -55,6 +55,7 @@ public:
 	bool Wait( RageTimer *pTimeout );
 	void Signal();
 	void Broadcast();
+	bool WaitTimeoutSupported() const;
 
 private:
 	MutexImpl_Pthreads *m_pParent;

stepmania/src/arch/Threads/Threads_Win32.h

@@ -49,6 +49,7 @@ public:
 	bool Wait( RageTimer *pTimeout );
 	void Signal();
 	void Broadcast();
+	bool WaitTimeoutSupported() const { return true; }
 
 private:
 	MutexImpl_Win32 *m_pParent;