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/HMACEngine.h

@@ -0,0 +1,145 @@
+//
+// HMACEngine.h
+//
+// Library: Foundation
+// Package: Crypt
+// Module:  HMACEngine
+//
+// Definition of the HMACEngine class.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_HMACEngine_INCLUDED
+#define Foundation_HMACEngine_INCLUDED
+
+
+#include "Poco/Foundation.h"
+#include "Poco/DigestEngine.h"
+#include <cstring>
+
+
+namespace Poco {
+
+
+template <class Engine>
+class HMACEngine: public DigestEngine
+	/// This class implements the HMAC message
+	/// authentication code algorithm, as specified
+	/// in RFC 2104. The underlying DigestEngine
+	/// (MD5Engine, SHA1Engine, etc.) must be given as 
+	/// template argument.
+	/// Since the HMACEngine is a DigestEngine, it can
+	/// be used with the DigestStream class to create
+	/// a HMAC for a stream.
+{
+public:
+	enum
+	{
+		BLOCK_SIZE  = Engine::BLOCK_SIZE,
+		DIGEST_SIZE = Engine::DIGEST_SIZE
+	};
+	
+	HMACEngine(const std::string& passphrase)
+	{
+		init(passphrase.data(), passphrase.length());
+	}
+	
+	HMACEngine(const char* passphrase, std::size_t length)
+	{
+		poco_check_ptr (passphrase);
+
+		init(passphrase, length);
+	}
+	
+	~HMACEngine()
+	{
+		std::memset(_ipad, 0, BLOCK_SIZE);
+		std::memset(_opad, 0, BLOCK_SIZE);
+		delete [] _ipad;
+		delete [] _opad;
+	}
+		
+	std::size_t digestLength() const
+	{
+		return DIGEST_SIZE;
+	}
+	
+	void reset()
+	{
+		_engine.reset();
+		_engine.update(_ipad, BLOCK_SIZE);
+	}
+	
+	const DigestEngine::Digest& digest()
+	{
+		const DigestEngine::Digest& d = _engine.digest();
+		char db[DIGEST_SIZE];
+		char* pdb = db;
+		for (auto v: d) *pdb++ = v;
+		_engine.reset();
+		_engine.update(_opad, BLOCK_SIZE);
+		_engine.update(db, DIGEST_SIZE);
+		const DigestEngine::Digest& result = _engine.digest();
+		reset();
+		return result;
+	}
+
+protected:
+	void init(const char* passphrase, std::size_t length)
+	{
+		_ipad = new char[BLOCK_SIZE];
+		_opad = new char[BLOCK_SIZE];
+		std::memset(_ipad, 0, BLOCK_SIZE);
+		std::memset(_opad, 0, BLOCK_SIZE);
+		if (length > BLOCK_SIZE)
+		{
+			_engine.reset();
+			_engine.update(passphrase, length);
+			const DigestEngine::Digest& d = _engine.digest();
+			char* ipad = _ipad;
+			char* opad = _opad;
+			int n = BLOCK_SIZE;
+			for (DigestEngine::Digest::const_iterator it = d.begin(); it != d.end() && n-- > 0; ++it)
+			{
+				*ipad++ = *it;
+				*opad++ = *it;
+			}
+		}
+		else
+		{
+			std::memcpy(_ipad, passphrase, length);
+			std::memcpy(_opad, passphrase, length);
+		}
+		for (int i = 0; i < BLOCK_SIZE; ++i)
+		{
+			_ipad[i] ^= 0x36;
+			_opad[i] ^= 0x5c;
+		}
+		reset();
+	}
+	
+	void updateImpl(const void* data, std::size_t length)
+	{
+		_engine.update(data, length);
+	}
+
+private:
+	HMACEngine();
+	HMACEngine(const HMACEngine&);
+	HMACEngine& operator = (const HMACEngine&);
+
+	Engine _engine;
+	char*  _ipad;
+	char*  _opad;
+};
+
+
+} // namespace Poco
+
+
+#endif // Foundation_HMACEngine_INCLUDED