Add Android.mk and build package as a static library

Added an Android.mk file that builds the package as a static library called
libmodpb64.

Bug: 22353299
Change-Id: I00dd9ceede22c30f8883a1a7b917d317f0b92b6d

Android.mk

diff --git a/Android.mk b/Android.mk
new file mode 100644
index 0000000..9892c72
--- /dev/null
+++ b/Android.mk
@@ -0,0 +1,22 @@
+# Copyright (C) 2015 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)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libmodpb64
+LOCAL_SRC_FILES := modp_b64.cc
+LOCAL_CPP_EXTENSION := .cc
+LOCAL_CFLAGS := -Wall -Werror
+include $(BUILD_STATIC_LIBRARY)

modp_b64_data.h

diff --git a/modp_b64_data.h b/modp_b64_data.h
index fb85890..2ecf597 100644
--- a/modp_b64_data.h
+++ b/modp_b64_data.h
@@ -1,4 +1,3 @@
-#include "build/build_config.h"
 #include <stdint.h>
 
 #define CHAR62 '+'