Fix Irrlicht 1.9 support

Author: sfan5

src/gui/guiButton.h

@@ -14,7 +14,7 @@
 
 using namespace irr;
 
-#if (IRRLICHT_VERSION_MAJOR > 1 || IRRLICHT_VERSION_MINOR != 8 || IRRLICHT_VERSION_REVISION < 5)
+#if (IRRLICHT_VERSION_MAJOR == 1 && IRRLICHT_VERSION_MINOR <= 8)
 	namespace irr { namespace gui {
 
 		//! State of buttons used for drawing texture images.
@@ -142,9 +142,11 @@ class GUIButton : public gui::IGUIButton
 						   video::SColor color=video::SColor(255,255,255,255),
 						   bool loop=false, bool scale=false);
 
+#if (IRRLICHT_VERSION_MAJOR == 1 && IRRLICHT_VERSION_MINOR <= 8)
 	void setSprite(gui::EGUI_BUTTON_STATE state, s32 index, video::SColor color, bool loop) override {
 		setSprite(state, index, color, loop, false);
 	}
+#endif
 
 	//! Get the sprite-index for the given state or -1 when no sprite is set
 	virtual s32 getSpriteIndex(gui::EGUI_BUTTON_STATE state) const;