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/NamedMutex_UNIX.h

@@ -0,0 +1,57 @@
+//
+// NamedMutex_UNIX.h
+//
+// Library: Foundation
+// Package: Processes
+// Module:  NamedMutex
+//
+// Definition of the NamedMutexImpl class for Unix.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_NamedMutex_UNIX_INCLUDED
+#define Foundation_NamedMutex_UNIX_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#if defined(sun) || defined(__APPLE__) || defined(__osf__) || defined(__QNX__) || defined(_AIX)
+#include <semaphore.h>
+#endif
+
+
+namespace Poco {
+
+
+class Foundation_API NamedMutexImpl
+{
+protected:
+	NamedMutexImpl(const std::string& name);
+	~NamedMutexImpl();
+	void lockImpl();
+	bool tryLockImpl();
+	void unlockImpl();
+	
+private:
+	std::string getFileName();
+
+	std::string _name;
+#if defined(sun) || defined(__APPLE__) || defined(__osf__) || defined(__QNX__) || defined(_AIX)
+	sem_t* _sem;
+#else
+	int _semid;  // semaphore id
+	bool _owned;
+#endif
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_NamedMutex_UNIX_INCLUDED