Purge some dead code (mostly Irrlicht) (#16111)

* Remove obsolete Irrlicht attributes system

* Remove dead GUI element types

* Remove some obsolete Irrlicht headers

* Fix some oopsies from d96f5e1

src/gui/guiFormSpecMenu.cpp

@@ -10,9 +10,11 @@
 #include <limits>
 #include <sstream>
 #include "guiFormSpecMenu.h"
+#include "EGUIElementTypes.h"
 #include "constants.h"
 #include "gamedef.h"
 #include "client/keycode.h"
+#include "gui/guiTable.h"
 #include "util/strfnd.h"
 #include <IGUIButton.h>
 #include <IGUICheckBox.h>
@@ -198,7 +200,7 @@ void GUIFormSpecMenu::setInitialFocus()
 
 	// 3. first table
 	for (gui::IGUIElement *it : children) {
-		if (it->getTypeName() == std::string("GUITable")) {
+		if (it->getType() == gui::EGUIET_TABLE) {
 			Environment->setFocus(it);
 			return;
 		}

src/gui/guiScene.cpp

@@ -8,7 +8,6 @@
 #include <IAnimatedMeshSceneNode.h>
 #include <IVideoDriver.h>
 #include <ISceneManager.h>
-#include "IAttributes.h"
 #include "porting.h"
 #include "client/mesh.h"
 
@@ -21,8 +20,6 @@ GUIScene::GUIScene(gui::IGUIEnvironment *env, scene::ISceneManager *smgr,
 
 	m_cam = m_smgr->addCameraSceneNode(0, v3f(0.f, 0.f, -100.f), v3f(0.f));
 	m_cam->setFOV(30.f * core::DEGTORAD);
-
-	m_smgr->getParameters()->setAttribute(scene::ALLOW_ZWRITE_ON_TRANSPARENT, true);
 }
 
 GUIScene::~GUIScene()

src/gui/guiTable.cpp

@@ -635,11 +635,6 @@ void GUITable::setDynamicData(const DynamicData &dyndata)
 	m_scrollbar->setPos(dyndata.scrollpos);
 }
 
-const c8* GUITable::getTypeName() const
-{
-	return "GUITable";
-}
-
 void GUITable::updateAbsolutePosition()
 {
 	IGUIElement::updateAbsolutePosition();

src/gui/guiTable.h

@@ -118,9 +118,6 @@ public:
 	/* Set selection, scroll position and opened (sub)trees */
 	void setDynamicData(const DynamicData &dyndata);
 
-	/* Returns "GUITable" */
-	virtual const c8* getTypeName() const;
-
 	/* Must be called when position or size changes */
 	virtual void updateAbsolutePosition();