[auto_schedule] How to setup auto_schedule tuning with armv7a device?

Hello, I follow the tutorial tune-network-arm for tuning a simple conv model on armv7a device with RPC tracker. But it seems hard to setup correctly, there comes some problem, the first one is below.

The first problem is compile tvm for armv7a, get an error:

src/tir/usmp/algo/hill_climb.cc:275:13: error: use of undeclared identifier 'rand_r'
            rnd_func() % 100 < static_cast<int>(50 * (total - total_size) / total / attempts)))) {
            ^
src/tir/usmp/algo/hill_climb.cc:202:20: note: expanded from macro 'rnd_func'
#define rnd_func() rand_r(&_seedp)
TVM version: commit 7315c9d5b46408a047409f1e047cb6b7779c668e (HEAD, tag: v0.14.0.rc0, tag: v0.14.0, origin/v0.14.0)
Target Device: (Hardware: RK3188, OS: Android-19 (armeabi-v7a))
TVM compile on Host Device: (Hardware: PC (x86_64), OS: Ubuntu 18.04.6)

CMake compile command is:

cmake .. \
-G Ninja \
-DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake \
-DANDROID_ABI="armeabi-v7a" \
-DANDROID_STL=c++_static \
-DANDROID_NATIVE_API_LEVEL=android-19  \
-DANDROID_TOOLCHAIN=clang \
-DUSE_CPP_RPC=ON \
-DUSE_LLVM=OFF \
-DUSE_MLIR=OFF \
-DCMAKE_BUILD_TYPE=Release
ninja

Need your help, thanks in advance.