Major plugin refactor and cleanup.

Switched to POCO library for unified platform/library interface.
Deprecated the external module API. It was creating more problems than solving.
Removed most built-in libraries in favor of system libraries for easier maintenance.
Cleaned and secured code with help from static analyzers.

vendor/POCO/Foundation/include/Poco/Semaphore_POSIX.h

@@ -0,0 +1,75 @@
+//
+// Semaphore_POSIX.h
+//
+// Library: Foundation
+// Package: Threading
+// Module:  Semaphore
+//
+// Definition of the SemaphoreImpl class for POSIX Threads.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_Semaphore_POSIX_INCLUDED
+#define Foundation_Semaphore_POSIX_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/Exception.h"
+#include <pthread.h>
+#include <errno.h>
+
+
+namespace Poco {
+
+
+class Foundation_API SemaphoreImpl
+{
+protected:
+	SemaphoreImpl(int n, int max);		
+	~SemaphoreImpl();
+	void setImpl();
+	void waitImpl();
+	bool waitImpl(long milliseconds);
+	
+private:
+	volatile int    _n;
+	int             _max;
+	pthread_mutex_t _mutex;
+	pthread_cond_t  _cond;
+};
+
+
+//
+// inlines
+//
+inline void SemaphoreImpl::setImpl()
+{
+	if (pthread_mutex_lock(&_mutex))	
+		throw SystemException("cannot signal semaphore (lock)");
+	if (_n < _max)
+	{
+		++_n;
+	}
+	else
+	{
+		pthread_mutex_unlock(&_mutex);
+		throw SystemException("cannot signal semaphore: count would exceed maximum");
+	}	
+	if (pthread_cond_signal(&_cond))
+	{
+		pthread_mutex_unlock(&_mutex);
+		throw SystemException("cannot signal semaphore");
+	}
+	pthread_mutex_unlock(&_mutex);
+}
+
+
+} // namespace Poco
+
+
+#endif // Foundation_Semaphore_POSIX_INCLUDED