provide main classpath again, notably for cold-start;

--- a/src/Pure/Tools/main.scala	Wed Sep 11 21:40:03 2013 +0200
+++ b/src/Pure/Tools/main.scala	Wed Sep 11 22:46:51 2013 +0200
@@ -16,6 +16,20 @@
 
 object Main
 {
+  /** class path **/
+
+  def class_path: List[Path] = List(
+    "$ISABELLE_HOME/lib/classes/ext/Pure.jar",
+    "$ISABELLE_HOME/lib/classes/ext/scala-compiler.jar",
+    "$ISABELLE_HOME/lib/classes/ext/scala-library.jar",
+    "$ISABELLE_HOME/lib/classes/ext/scala-swing.jar",
+    "$ISABELLE_HOME/lib/classes/ext/scala-actors.jar",
+    "$ISABELLE_HOME/lib/classes/ext/scala-reflect.jar",
+    "$ISABELLE_HOME/src/Tools/jEdit/dist/jedit.jar"
+  ).map(Path.explode(_))
+
+
+
   /** main entry point **/
 
   def main(args: Array[String])

--- a/src/Tools/jEdit/src/scala_console.scala	Wed Sep 11 21:40:03 2013 +0200
+++ b/src/Tools/jEdit/src/scala_console.scala	Wed Sep 11 22:46:51 2013 +0200
@@ -46,7 +46,9 @@
         find_files(new JFile(start),
           entry => entry.isFile && entry.getName.endsWith(".jar")).map(_.getAbsolutePath)
       else Nil
-    val path = find_jars(jEdit.getSettingsDirectory) ::: find_jars(jEdit.getJEditHome)
+    val path =
+      Main.class_path.map(Isabelle_System.platform_file(_)) :::
+      find_jars(jEdit.getSettingsDirectory) ::: find_jars(jEdit.getJEditHome)
     path.mkString(JFile.pathSeparator)
   }