FAILURE: Build failed with an exception.
Build command failed.
Error while executing process /Users/Gain/Library/Android/sdk/cmake/3.6.4111459/bin/cmake with arguments {--build /Users/Gain/job/code/github/AoE/Android/third_party/mnn/.externalNativeBuild/cmake/release/arm64-v8a --target mnncore}
[1/3] Building CXX object CMakeFiles/mnncore.dir/src/main/jni/mnnnetnative.cpp.o
[2/3] Building CXX object CMakeFiles/mnncore.dir/src/main/jni/mnnportraitnative.cpp.o
[3/3] Linking CXX shared library ../../../../build/intermediates/cmake/release/obj/arm64-v8a/libmnncore.so
FAILED: : && /Users/Gain/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++ -target aarch64-none-linux-android -gcc-toolchain /Users/Gain/Library/Android/sdk/ndk-bundle/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64 --sysroot=/Users/Gain/Library/Android/sdk/ndk-bundle/platforms/android-21/arch-arm64 -fPIC -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -fno-exceptions -fno-rtti -std=c++11 -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -fno-exceptions -fno-rtti -std=c++11 -fopenmp -std=c++11 -fvisibility=hidden -fvisibility-inlines-hidden -fomit-frame-pointer -fstrict-aliasing -ffunction-sections -fdata-sections -ffast-math -fno-rtti -fno-exceptions -flax-vector-conversions -O2 -DNDEBUG -O2 -DNDEBUG -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -Wl,--build-id -Wl,--warn-shared-textrel -Wl,--fatal-warnings -Wl,--no-undefined -Wl,-z,noexecstack -Qunused-arguments -Wl,-z,relro -Wl,-z,now -shared -Wl,-soname,libmnncore.so -o ../../../../build/intermediates/cmake/release/obj/arm64-v8a/libmnncore.so CMakeFiles/mnncore.dir/src/main/jni/mnnnetnative.cpp.o CMakeFiles/mnncore.dir/src/main/jni/mnnportraitnative.cpp.o ../../../../libs/arm64-v8a/libMNN.so -llog -ljnigraphics -lm "/Users/Gain/Library/Android/sdk/ndk-bundle/sources/cxx-stl/llvm-libc++/libs/arm64-v8a/libc++_shared.so" && :
/Users/Gain/Library/Android/sdk/ndk-bundle/toolchains/aarch64-linux-android-4.9/prebuilt/darwin-x86_64/lib/gcc/aarch64-linux-android/4.9.x/../../../../aarch64-linux-android/bin/ld: cannot find -lrt
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.