resolve_o()
{
    [ -n "$O" ] && return

    if [ -f ".config" ] && [ -d "output" ]; then
	# Buildroot
	O=$(readlink -f ./output)
    elif [ -f "output/.config" ]; then
	# BR2_EXTERNAL
	O=$(readlink -f ./output)
    elif [ -f ".config" ] && [ -d "host" ]; then
	# Called from inside output/ directory
	O=$(readlink -f .)
    else
	echo "*** Error: cannot find Buildroot output dir!" >&2
	exit 1
    fi
}

resolve_host_dir()
{
    [ -n "$HOST_DIR" ] && return

    resolve_o

    if ! [ -d "$O/host" ]; then
	echo "*** Error: cannot find Buildroot host binaries dir!" >&2
	exit 1
    fi

    HOST_DIR="$O/host"
}