First make sure you have a Frida checkout built for android-x86, somewhere outside the art-tracer repo:
git clone --recurse-submodules https://github.com/frida/frida.git
cd frida
make build/frida-android-x86/lib/pkgconfig/frida-core-1.0.pc
Then in here:
(not necessary??) export FRIDA=/path/to/frida/checkout
export NDK_TOOLCHAIN=/path/to/toolchain
make build
make deploy