A few fixes in the extension C API

- Add MethodBind call (besides ptrcall), since vararg methods don't work
  with ptrcall.
- Fix argument name in register constant function to the way it
  actually is used in the engine.
- Change the integer constant type to GDNativeInt to keep it consistent.

core/extension/gdnative_interface.cpp

@@ -663,7 +663,23 @@ static const char32_t *gdnative_string_operator_index_const(const GDNativeString
 
 /* OBJECT API */
 
-static void gdnative_object_method_bind_ptrcall(GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeTypePtr *p_args, GDNativeTypePtr p_ret) {
+static void gdnative_object_method_bind_call(const GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeVariantPtr *p_args, GDNativeInt p_arg_count, GDNativeVariantPtr r_return, GDNativeCallError *r_error) {
+	MethodBind *mb = (MethodBind *)p_method_bind;
+	Object *o = (Object *)p_instance;
+	const Variant **args = (const Variant **)p_args;
+	Callable::CallError error;
+
+	Variant ret = mb->call(o, args, p_arg_count, error);
+	memnew_placement(r_return, Variant(ret));
+
+	if (r_error) {
+		r_error->error = (GDNativeCallErrorType)(error.error);
+		r_error->argument = error.argument;
+		r_error->expected = error.expected;
+	}
+}
+
+static void gdnative_object_method_bind_ptrcall(const GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeTypePtr *p_args, GDNativeTypePtr p_ret) {
 	MethodBind *mb = (MethodBind *)p_method_bind;
 	Object *o = (Object *)p_instance;
 	mb->ptrcall(o, (const void **)p_args, p_ret);
@@ -829,6 +845,7 @@ void gdnative_setup_interface(GDNativeInterface *p_interface) {
 
 	/* OBJECT */
 
+	gdni.object_method_bind_call = gdnative_object_method_bind_call;
 	gdni.object_method_bind_ptrcall = gdnative_object_method_bind_ptrcall;
 	gdni.object_destroy = gdnative_object_destroy;
 	gdni.global_get_singleton = gdnative_global_get_singleton;

core/extension/gdnative_interface.h

@@ -389,7 +389,8 @@ typedef struct {
 
 	/* OBJECT */
 
-	void (*object_method_bind_ptrcall)(GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeTypePtr *p_args, GDNativeTypePtr r_ret);
+	void (*object_method_bind_call)(const GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeVariantPtr *p_args, GDNativeInt p_arg_count, GDNativeVariantPtr r_ret, GDNativeCallError *r_error);
+	void (*object_method_bind_ptrcall)(const GDNativeMethodBindPtr p_method_bind, GDNativeObjectPtr p_instance, const GDNativeTypePtr *p_args, GDNativeTypePtr r_ret);
 	void (*object_destroy)(GDNativeObjectPtr p_o);
 	GDNativeObjectPtr (*global_get_singleton)(const char *p_name);
 	void *(*object_get_instance_binding)(GDNativeObjectPtr p_o, void *p_token, const GDNativeInstanceBindingCallbacks *p_callbacks);
@@ -409,7 +410,7 @@ typedef struct {
 
 	void (*classdb_register_extension_class)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_parent_class_name, const GDNativeExtensionClassCreationInfo *p_extension_funcs);
 	void (*classdb_register_extension_class_method)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const GDNativeExtensionClassMethodInfo *p_method_info);
-	void (*classdb_register_extension_class_integer_constant)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_enum_name, const char *p_class_name, const char *p_constant_name, uint32_t p_constant_value);
+	void (*classdb_register_extension_class_integer_constant)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_enum_name, const char *p_constant_name, GDNativeInt p_constant_value);
 	void (*classdb_register_extension_class_property)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const GDNativePropertyInfo *p_info, const char *p_setter, const char *p_getter);
 	void (*classdb_register_extension_class_signal)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_signal_name, const GDNativePropertyInfo *p_argument_info, GDNativeInt p_argument_count);
 	void (*classdb_unregister_extension_class)(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name); /* Unregistering a parent class before a class that inherits it will result in failure. Inheritors must be unregistered first. */

core/extension/native_extension.h

@@ -48,7 +48,7 @@ class NativeExtension : public Resource {
 
 	static void _register_extension_class(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_parent_class_name, const GDNativeExtensionClassCreationInfo *p_extension_funcs);
 	static void _register_extension_class_method(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const GDNativeExtensionClassMethodInfo *p_method_info);
-	static void _register_extension_class_integer_constant(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_enum_name, const char *p_constant_name, uint32_t p_constant_value);
+	static void _register_extension_class_integer_constant(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_enum_name, const char *p_constant_name, GDNativeInt p_constant_value);
 	static void _register_extension_class_property(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const GDNativePropertyInfo *p_info, const char *p_setter, const char *p_getter);
 	static void _register_extension_class_signal(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name, const char *p_signal_name, const GDNativePropertyInfo *p_argument_info, GDNativeInt p_argument_count);
 	static void _unregister_extension_class(const GDNativeExtensionClassLibraryPtr p_library, const char *p_class_name);