想按照Tensorflow的安卓Demo的步骤把这个Demo编译一遍，可是不懂NDK，编译错误，错误信息如下：
tp@tp-Inspiron-3421:~/tensorflow$ /home/tp/bin/bazel build //tensorflow/examples/android:tensorflow_demo
..................
INFO: Found 1 target...
INFO: From Compiling external/re2/re2/stringpiece.cc:
external/re2/re2/stringpiece.cc:6:23: fatal error: util/util.h: No such file or directory
#include "util/util.h"
^
compilation terminated.
ERROR: /home/tp/.cache/bazel/_bazel_tp/52515bfa99a2d82b1037ec6d5029c6c1/external/re2/BUILD:7:1: C++ compilation of rule '@re2//:stringpiece' failed: arm-linux-androideabi-gcc failed: error executing command external/androidndk/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64/bin/arm-linux-androideabi-gcc -fstack-protector-strong -fpic -ffunction-sections -funwind-tables ... (remaining 37 argument(s) skipped).
Target //tensorflow/examples/android:tensorflow_demo failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 123.372s, Critical Path: 52.03s.
请问这是为什么？怎么解决？
