Win32: Use the nicer looking blender-drawn confirmation message box when

quitting with unsaved changes, instead of an ugly messagebox

intern/ghost/intern/GHOST_SystemWin32.cpp

@@ -1751,9 +1751,3 @@ int GHOST_SystemWin32::toggleConsole(int action)
 
 	return m_consoleStatus;
 }
-
-int GHOST_SystemWin32::confirmQuit(GHOST_IWindow *window) const
-{
-	return (MessageBox(window ? ((GHOST_WindowWin32 *)window)->getHWND() : 0, "Some changes have not been saved.\nDo you really want to quit?",
-	                   "Exit Blender", MB_OKCANCEL | MB_ICONWARNING | MB_TOPMOST) == IDOK);
-}