JAR signing logic for the apksigner-core library.

apksigner-code library will offer a high-level primitive (future
commit) for signing APKs. This is meant to be used by
build/tools/signapk and Android Studio's APK builder/signer.

This commit adds a lower-level JAR signing (aka v1 signing) code which
will be used by the future APK signing abstraction exposed by this
library.

All classes added by this commit are internal (i.e., implementation
details of this library). Clients of this library should not be using
these classes.

Bug: 26516150
Change-Id: I5cecd435e63aab206d63868be5e0d0e289e7c423
diff --git a/tools/apksigner/core/Android.mk b/tools/apksigner/core/Android.mk
new file mode 100644
index 0000000..c86208b
--- /dev/null
+++ b/tools/apksigner/core/Android.mk
@@ -0,0 +1,26 @@
+#
+# Copyright (C) 2016 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 := $(call my-dir)
+
+# apksigner library, for signing APKs and verification signatures of APKs
+# ============================================================
+include $(CLEAR_VARS)
+LOCAL_MODULE := apksigner-core
+LOCAL_SRC_FILES := $(call all-java-files-under, src)
+LOCAL_JAVA_LIBRARIES = \
+  bouncycastle-host \
+  bouncycastle-bcpkix-host
+include $(BUILD_HOST_JAVA_LIBRARY)