revert part of commit add0211522737b79dad990ccd65c8af63b5cc1dd

revert part of commit add0211522737b79dad990ccd65c8af63b5cc1dd

"use iswspace()/iswpunct() to find word delimiters

    this inverts the configuration logic: you no longer provide a list of
    delimiters -- all space and punctuation characters are considered
    delimiters, unless listed in extrawordchars."

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