Avoid cursor changes under Linux if visibility doesn't change.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@2095 dfc29bdd-3216-0410-991c-e03cc46cb475

source/Irrlicht/CIrrDeviceLinux.h

@@ -147,6 +147,8 @@ namespace irr
 			//! Changes the visible state of the mouse cursor.
 			virtual void setVisible(bool visible)
 			{
+				if (visible==IsVisible)
+					return;
 				IsVisible = visible;
 #ifdef _IRR_COMPILE_WITH_X11_
 				if (!Null)