Add import_build_vars to shell_utils.sh

    ' SIGINT SIGTERM SIGQUIT EXIT

}

# Import the build variables supplied as arguments into this shell's environment.

# For absolute variables, prefix the variable name with a '/'. For example:

#    import_build_vars OUT_DIR DIST_DIR /HOST_OUT_EXECUTABLES

# Returns nonzero if the build command failed. Stderr is passed through.

function import_build_vars()

{

    require_top

    local script

    script=$(cd $TOP && build/soong/bin/get_build_vars "$@")

    local ret=$?

    if [ $ret -ne 0 ] ; then

        return $ret

    fi

    eval "$script"

    return $?

}