Comment 1 for bug 1160047

I think this entire segment

        TMPDIR=${TMPDIR:-""}
        if [ -z "${TMPDIR}" ]; then
            # try to get it from my.cnf
            TMPDIR=$(grep -E '^\s*tmpdir' $WSREP_SST_OPT_CONF | \
                     awk -F = '{ print $2 }' | sed 's/^\s//g' | sed 's/\s.*//g' )
            # if failed default to /tmp
            [ -z "${TMPDIR}" ] && TMPDIR="/tmp"
        fi

is not required. If a separate tmpdir for xtrabackup is required
(by default it will use mysql's), then it can be passed through
tmpdir variable under [xtrabackup] in my.cnf