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/Platform_POSIX.h

@@ -0,0 +1,53 @@
+//
+// Platform_POSIX.h
+//
+// Library: Foundation
+// Package: Core
+// Module:  Platform
+//
+// Platform and architecture identification macros
+// and platform-specific definitions for various POSIX platforms
+//
+// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// SPDX-License-Identifier:	BSL-1.0
+//
+
+
+#ifndef Foundation_Platform_POSIX_INCLUDED
+#define Foundation_Platform_POSIX_INCLUDED
+
+
+//
+// PA-RISC based HP-UX platforms have some issues...
+//
+#if defined(hpux) || defined(_hpux)
+	#if defined(__hppa) || defined(__hppa__)
+		#define POCO_NO_SYS_SELECT_H 1
+		#if defined(__HP_aCC)
+			#define POCO_NO_TEMPLATE_ICOMPARE 1
+		#endif
+	#endif
+#endif
+
+
+//
+// Thread-safety of local static initialization
+//
+#if __cplusplus >= 201103L || __GNUC__ >= 4 || defined(__clang__)
+	#ifndef POCO_LOCAL_STATIC_INIT_IS_THREADSAFE
+		#define POCO_LOCAL_STATIC_INIT_IS_THREADSAFE 1
+	#endif
+#endif
+
+
+//
+// No syslog.h on QNX/BB10
+//
+#if defined(__QNXNTO__)
+	#define POCO_NO_SYSLOGCHANNEL
+#endif
+
+
+#endif // Foundation_Platform_POSIX_INCLUDED