Motivation: Android NDK is deprecating GCC and moving ot Clang/LLVM. From [1]:

We strongly recommend switching to Clang.
GCC in the NDK is now deprecated in favor of Clang.

This patch fixes the only one problem when migrating GCC to Clang.

In my build script, $CPP is set to "${ANDROID_NDK}/toolchains/llvm/prebuilt/linux-x86_64/bin/clang -E" and $CPPFLAGS is set to "-target armv7-none-linux-androideabi -gcc-toolchain ${ANDROID_NDK}/toolchains/arm-linux-androideabi-4.9/prebuilt/linux-x86_64 --sysroot ${ANDROID_NDK}/platforms/android-21/arch-arm/usr -I${PREFIX}/include -DANDROID". I'm not sure whether it's the correct usage of clang, but at least it works.

With such a configuration, most Python parts builds well. Just something wrong - extensions as built as xyz.cpython-36m-x86_64-linux-gnu.so. My patch just fixes $(PLATFORM_TRIPLET) detection.

[1] https://developer.android.com/ndk/downloads/revision_history.html