prefer internal tool;

--- a/lib/Tools/check_sources	Sun Apr 03 22:42:15 2016 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,9 +0,0 @@
-#!/usr/bin/env bash
-#
-# Author: Makarius
-#
-# DESCRIPTION: some sanity checks for Isabelle sources
-
-isabelle_admin_build jars || exit $?
-
-isabelle java isabelle.Check_Sources "$@"

--- a/src/Pure/System/isabelle_tool.scala	Sun Apr 03 22:42:15 2016 +0200
+++ b/src/Pure/System/isabelle_tool.scala	Sun Apr 03 22:45:40 2016 +0200
@@ -69,6 +69,7 @@
     }
 
   register(Build.isabelle_tool)
+  register(Check_Sources.isabelle_tool)
   register(Doc.isabelle_tool)
   register(Options.isabelle_tool)
 

--- a/src/Pure/Tools/check_sources.scala	Sun Apr 03 22:42:15 2016 +0200
+++ b/src/Pure/Tools/check_sources.scala	Sun Apr 03 22:45:40 2016 +0200
@@ -52,11 +52,11 @@
   }
 
 
-  /* command line entry point */
+  /* Isabelle tool wrapper */
 
-  def main(args: Array[String])
-  {
-    Command_Line.tool0 {
+  val isabelle_tool =
+    Isabelle_Tool("check_sources", "some sanity checks for Isabelle sources", args =>
+    {
       val getopts = Getopts("""
 Usage: isabelle check_sources [ROOT_DIRS...]
 
@@ -67,6 +67,5 @@
       if (specs.isEmpty) getopts.usage()
 
       for (root <- specs) check_hg(Path.explode(root))
-    }
-  }
+    })
 }