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/StreamUtil.h

@@ -0,0 +1,92 @@
+//
+// StreamUtil.h
+//
+// Library: Foundation
+// Package: Streams
+// Module:  StreamUtil
+//
+// Stream implementation support.
+//
+// Copyright (c) 2005-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_StreamUtil_INCLUDED
+#define Foundation_StreamUtil_INCLUDED
+
+
+#include "Poco/Foundation.h"
+
+
+// poco_ios_init
+//
+// This is a workaround for a bug in the Dinkumware
+// implementation of iostreams.
+//
+// Calling basic_ios::init() multiple times for the
+// same basic_ios instance results in a memory leak
+// caused by the ios' locale being allocated more than
+// once, each time overwriting the old pointer.
+// This usually occurs in the following scenario:
+//
+// class MyStreamBuf: public std::streambuf
+// {
+//     ...
+// };
+//
+// class MyIOS: public virtual std::ios
+// {
+// public:
+//     MyIOS()
+//     {
+//         init(&_buf);
+//     }
+// protected:
+//     MyStreamBuf _buf;
+// };
+//
+// class MyIStream: public MyIOS, public std::istream
+// {
+//     ...
+// };
+//
+// In this scenario, std::ios::init() is called twice
+// (the first time by the MyIOS constructor, the second
+// time by the std::istream constructor), resulting in 
+// two locale objects being allocated, the pointer second 
+// one overwriting the pointer to the first one and thus 
+// causing a memory leak.
+// 
+// The workaround is to call init() only once for each
+// stream object - by the istream, ostream or iostream
+// constructor, and not calling init() in ios-derived
+// base classes.
+//
+// Some stream implementations, however, require that
+// init() is called in the MyIOS constructor.
+// Therefore we replace each call to init() with
+// the poco_ios_init macro defined below.
+
+
+#if !defined(POCO_IOS_INIT_HACK)
+	// Microsoft Visual Studio with Dinkumware STL (but not STLport)
+#	if defined(_MSC_VER) && (!defined(_STLP_MSVC) || defined(_STLP_NO_OWN_IOSTREAMS))
+#		define POCO_IOS_INIT_HACK 1
+    // QNX with Dinkumware but not GNU C++ Library
+#	elif defined(__QNX__) && !defined(__GLIBCPP__)
+#		define POCO_IOS_INIT_HACK 1
+#	endif
+#endif
+
+
+#if defined(POCO_IOS_INIT_HACK)
+#	define poco_ios_init(buf)
+#else
+#	define poco_ios_init(buf) init(buf)
+#endif
+
+
+#endif // Foundation_StreamUtil_INCLUDED