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}

    echo
    echo "$*"
    echo
    exit 1
} >&2

# OS specific support (must be 'true' or 'false').
cygwin=false
msys=false
darwin=false
nonstop=false
case "$( uname )" in                #(
  CYGWIN* )         cygwin=true  ;; #(
  Darwin* )         darwin=true  ;; #(
  MSYS* | MINGW* )  msys=true    ;; #(
  NONSTOP* )        nonstop=true ;;
esac

CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar

  mkdir -p "${TARGET_OUT_LINUX}"
  cp "${ZTUNNEL_BIN_PATH}" "${TARGET_OUT_LINUX}/ztunnel"
  popd
}

# ztunnel binary vars (TODO handle debug builds, arm, darwin etc.)
ISTIO_ZTUNNEL_BASE_URL="${ISTIO_ZTUNNEL_BASE_URL:-https://storage.googleapis.com/istio-build/ztunnel}"

# If we are not using the default, assume its private and we need to authenticate

	## All binaries are static make sure to disable CGO.
	export CGO_ENABLED=0

	## List of architectures and OS to test coss compilation.
	SUPPORTED_OSARCH="linux/ppc64le linux/mips64 linux/amd64 linux/arm64 linux/s390x darwin/arm64 darwin/amd64 freebsd/amd64 windows/amd64 linux/arm linux/386 netbsd/amd64 linux/mips openbsd/amd64"
}

function _build() {
	local osarch=$1
	IFS=/ read -r -a arr <<<"$osarch"
	os="${arr[0]}"
	arch="${arr[1]}"

    echo 'behavior, create a new shell.'
    cat "$FROM_ENV"
    source "$FROM_ENV"
    rm "$FROM_ENV"
  fi
fi

# Mac builds have some specific setup needs. See setup_macos.sh for details
if [[ "${OSTYPE}" =~ darwin* ]]; then
  source ./ci/official/utilities/setup_macos.sh
fi

# Create and expand to the full path of TFCI_OUTPUT_DIR
export TFCI_OUTPUT_DIR=$(realpath "$TFCI_OUTPUT_DIR")
mkdir -p "$TFCI_OUTPUT_DIR"