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/samples/grep/src/grep.cpp

@@ -0,0 +1,61 @@
+//
+// grep.cpp
+//
+// This sample demonstrates the RegularExpression class.
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#include "Poco/RegularExpression.h"
+#include <iostream>
+
+
+using Poco::RegularExpression;
+
+
+int main(int argc, char** argv)
+{
+	if (argc < 2)
+	{
+		std::cout << "usage: " << argv[0] << ": [-i] [-x] pattern" << std::endl;
+		return 1;
+	}
+	
+	std::string pattern;
+	int options = 0;
+	for (int i = 1; i < argc; ++i)
+	{
+		std::string arg(argv[i]);
+		if (arg == "-i")
+			options += RegularExpression::RE_CASELESS;
+		else if (arg == "-x")
+			options += RegularExpression::RE_EXTENDED;
+		else
+			pattern = arg;
+	}
+	
+	RegularExpression re(pattern, options);
+	
+	int c = std::cin.get();
+	while (c != -1)
+	{
+		std::string line;
+		while (c != -1 && c != '\n')
+		{
+			line += (char) c;
+			c = std::cin.get();
+		}
+
+		RegularExpression::Match mtch;
+		if (re.match(line, mtch))
+			std::cout << line << std::endl;
+
+		if (c != -1) c = std::cin.get();
+	}
+	
+	return 0;
+}