using plain ISABELLE_PROCESS

--- a/lib/Tools/codegen	Mon Mar 02 08:15:54 2009 +0100
+++ b/lib/Tools/codegen	Mon Mar 02 08:26:03 2009 +0100
@@ -36,6 +36,5 @@
 THY=$(echo $THY | sed -e 's/\\/\\\\"/g; s/"/\\\"/g')
 ISAR="theory Codegen imports \"$THY\" begin export_code $CMD end"
 
-export ISABELLE_LINE_EDITOR=""
-echo "$ISAR" | "$ISABELLE_TOOL" tty -l "$IMAGE"
+echo "$ISAR" | "$ISABELLE_PROCESS" -I "$IMAGE"
 exit ${PIPESTATUS[1]}