To use the go tool to run individual programs and tests, put $GOROOT/bin into PATH to ensure
the go_ios_$GOARCH_exec wrapper is found. For example, to run the archive/tar tests:

	export PATH=$GOROOT/bin:$PATH
	GOOS=ios GOARCH=amd64 CGO_ENABLED=1 go test archive/tar

The go_ios_exec wrapper uses GOARCH to select the emulator (amd64) or the device (arm64).
However, further setup is required to run tests or programs directly on a device.

mobile subrepository:

	https://github.com/golang/mobile

To run the standard library tests, enable Cgo and use an appropriate
C compiler from the Android NDK. For example,

	CGO_ENABLED=1 \
	GOOS=android \
	GOARCH=arm64 \
	CC_FOR_TARGET=$NDK/toolchains/llvm/prebuilt/linux-x86_64/bin/aarch64-linux-android21-clang \
	./all.bash

To run tests on the Android device, add the bin directory to PATH so the

Empty directory for test, see https://golang.org/issues/29837....