if [[ ${TARGET_OS} ]]; then
    # Target explicitly set
    :
elif [[ $LOCAL_OS == Linux ]]; then
    TARGET_OS=linux
    readlink_flags="-f"
elif [[ $LOCAL_OS == Darwin ]]; then
    TARGET_OS=darwin
    readlink_flags=""
else
    echo "This system's OS, $LOCAL_OS, isn't supported"
    exit 1
fi

# Build image to use
TOOLS_REGISTRY_PROVIDER=${TOOLS_REGISTRY_PROVIDER:-gcr.io}

curl -sS -L -O https://www.iana.org/time-zones/repository/releases/tzdata$DATA.tar.gz
tar xzf tzcode$CODE.tar.gz
tar xzf tzdata$DATA.tar.gz

if ! make CFLAGS=-DSTD_INSPIRED AWK=awk TZDIR=zoneinfo posix_only >make.out 2>&1; then
	cat make.out
	exit 2
fi

cd zoneinfo
../mkzip ../../zoneinfo.zip
cd ../..

files="update.bash zoneinfo.zip"
modified=true

	unset GOARM
	if [ "$GOARCH" = "arm5" ]; then
		export GOARCH=arm
		export GOARM=5
	fi

	# Build and vet everything.
	# cmd/go/internal/work/exec.go enables the same vet flags during go test of std cmd
	# and should be kept in sync with any vet flag changes here.
	if ! "$GOROOT/bin/go" build std cmd || ! "$GOROOT/bin/go" vet -unsafeptr=false std cmd; then
		failed=true
		if $sete; then
			exit 1
		fi
	fi
done

done < "${BUILDINFO}"

OPTIMIZATION_FLAGS=(-trimpath)
if [ "${DEBUG}" == "1" ]; then
    OPTIMIZATION_FLAGS=()
fi

time GOOS=${BUILD_GOOS} GOARCH=${BUILD_GOARCH} ${GOBINARY} build \
        ${V} "${GOBUILDFLAGS_ARRAY[@]}" ${GCFLAGS:+-gcflags "${GCFLAGS}"} \
        -o "${OUT}" \
        "${OPTIMIZATION_FLAGS[@]}" \
        -pkgdir="${GOPKG}/${BUILD_GOOS}_${BUILD_GOARCH}" \