diff --git a/tools/Android.mk b/tools/Android.mk
new file mode 100644
index 0000000..aea2785
--- /dev/null
+++ b/tools/Android.mk
@@ -0,0 +1,23 @@
+#
+# Copyright (C) 2010 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+LOCAL_PATH := $(my-dir)
+
+ifeq ($(strip $(is_unbundled_app_build)),true)
+include $(LOCAL_PATH)/signapk/Android.mk
+else
+include $(call first-makefiles-under,$(LOCAL_PATH))
+endif