Add: [Script] Native priority queue; useful e.g. for pathfinders.

src/script/script_instance.cpp

@@ -58,6 +58,7 @@ ScriptInstance::ScriptInstance(const char *APIName) :
 	is_save_data_on_stack(false),
 	suspend(0),
 	is_paused(false),
+	in_shutdown(false),
 	callback(nullptr)
 {
 	this->storage = new ScriptStorage();
@@ -136,6 +137,7 @@ bool ScriptInstance::LoadCompatibilityScripts(const char *api_version, Subdirect
 ScriptInstance::~ScriptInstance()
 {
 	ScriptObject::ActiveInstance active(this);
+	this->in_shutdown = true;
 
 	if (instance != nullptr) this->engine->ReleaseObject(this->instance);
 	if (engine != nullptr) delete this->engine;
@@ -154,6 +156,7 @@ void ScriptInstance::Died()
 {
 	DEBUG(script, 0, "The script died unexpectedly.");
 	this->is_dead = true;
+	this->in_shutdown = true;
 
 	this->last_allocated_memory = this->GetAllocatedMemory(); // Update cache
 
@@ -718,3 +721,8 @@ size_t ScriptInstance::GetAllocatedMemory() const
 	if (this->engine == nullptr) return this->last_allocated_memory;
 	return this->engine->GetAllocatedMemory();
 }
+
+void ScriptInstance::ReleaseSQObject(HSQOBJECT *obj)
+{
+	if (!this->in_shutdown) this->engine->ReleaseObject(obj);
+}