Instantiate and hook up the plugin providers in the main() function of the corresponding backends (porters may have to update their ports if they were using the POSIX or Win32 module loading code implicitly); some cleanup

svn-id: r24153

backends/plugins/win32/win32-provider.cpp

@@ -71,6 +71,7 @@ public:
 		if (_dlHandle) {
 			if (!FreeLibrary((HMODULE)_dlHandle))
 				warning("Failed unloading plugin '%s'", _filename.c_str());
+			_dlHandle = 0;
 		}
 	}
 };