Admin/lib/Tools/build_setup

 for SRC in "${SOURCES[@]}"
 do
   ARGS["${#ARGS[@]}"]="$(platform_path "$ISABELLE_HOME/src/Tools/Setup/isabelle/setup/$SRC")"
 done
 
-isabelle_jdk javac -d "$TARGET_DIR" "${ARGS[@]}" || \
+isabelle_jdk javac -d "$TARGET_DIR" -classpath "$(platform_path "$ISABELLE_CLASSPATH")" "${ARGS[@]}" || \
   fail "Failed to compile sources"
 
 isabelle_jdk jar -c -f "$(platform_path "$TARGET_DIR/isabelle_setup.jar")" \
   -e "isabelle.setup.Setup" -C "$TARGET_DIR" isabelle || fail "Failed to produce jar"