[XML Markers] Convert XML Parser Standalone Binary to GDNative Library

[AsherGlick]

Eventually the XML parser needs to have hooks that are callable from inside gdscript. The best way for this to happen is to migrate the C++ Standalone XML parser to instead be compiled as a gdnative library.

[AsherGlick]

The API for this interface should be pretty similar to what is possible over a theoretical CLI interface.

We want to have these four functions

• read_taco(file)
• write_taco(file, root_category)
• read_waypoint_file(file)
• write_waypoint_file(file, root category, mapid)

So if we were to make a single interface that could be called via ipc or the cli it could look like this:

struct TacoOutput{
    string file; // A .zip, .taco file or a folder
    ? root_category; // Some variable denoting the category
}
struct WaypointOutput {
    string file; // A ?.waypoint? or a folder
    ? root_category: // Some variable denoting the category
    int32 mapid_filter; // A way to filter out data not in a map
}

void run(
    vector<string> xml_inputs
    vector<TacoOutput> xml_outputs,
    vector<string> waypoint_inputs
    vector<WaypointOutput> waypoint_outputs
) {
    for (xml_input in xml_inputs) {
        read_taco(xml_input);
    }
    for (waypoint_input in waypoint_inputs) {
        load_waypoint(waypoint_input);
    }
    for (xml_output in xml_outputs) {
        write_taco(xml_output.file, xml_output.root_category);
    }
    for (waypoint_output in waypoint_outputs) {
        write_waypoint(waypoint_output.file, waypoint_output.root_category, waypoint_output.mapid_filter);
    }
}

The type of the marker category identifier will be determined after the protobuf schema as it exists today is finalized, because it is changing how marker categories are stored.