src/Pure/System/isabelle_system.scala

 
   /** external processes **/
 
   /* raw execute for bootstrapping */
 
-  private def raw_execute(cwd: JFile, env: Map[String, String], redirect: Boolean, args: String*)
-    : Process =
+  def raw_execute(cwd: JFile, env: Map[String, String], redirect: Boolean, args: String*): Process =
   {
     val cmdline = new java.util.LinkedList[String]
     for (s <- args) cmdline.add(s)
 
     val proc = new ProcessBuilder(cmdline)