src/Pure/System/isabelle_system.scala

       {
         val isabelle_symbols = settings.getOrElse("ISABELLE_SYMBOLS", "")
         if (isabelle_symbols == "") error("Undefined environment variable: ISABELLE_SYMBOLS")
         val files =
           Path.split(isabelle_symbols).map(p => new File(standard_system.jvm_path(p.implode)))
-        new Symbol.Interpretation(Standard_System.try_read(files).split("\n").toList)
+        new Symbol.Interpretation(split_lines(Standard_System.try_read(files)))
       }
 
       _state = Some(State(standard_system, settings, symbols))
     }
   }