WARNING:__main__:make_standalone_toolchain.py is no longer necessary

[joshjdevl]

WARNING:main:make_standalone_toolchain.py is no longer necessary. The
$NDK/toolchains/llvm/prebuilt/linux-x86_64/bin directory contains target-specific scripts that perform
the same task. For example, instead of:

$ python $NDK/build/tools/make_standalone_toolchain.py \
    --arch arm --api 16 --install-dir toolchain
$ toolchain/bin/clang++ src.cpp

Instead use:

$ $NDK/toolchains/llvm/prebuilt/linux-x86_64/bin/armv7a-linux-androideabi16-clang++ src.cpp