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Please give virtual kick a person who wrote

    if ${MAKEINFO} --version \
       | egrep 'texinfo[^0-9]*([1-3][0-9]|4\.[4-9]|[5-9])' >/dev/null 2>&1; then
      :
    else
      MAKEINFO="$MISSING makeinfo"
    fi

This is a good example why regexp clowns should be berried more than 6 feet under, or they should be paid not to code at all.

Reader's excercise to solve what's wrong...