Issue #3215760 by fjgarlin: Argument 1 passed to _image_captcha_check_fonts()...

  if ($check_fonts) {

    // Check availability of enabled fonts.

    $fonts = _image_captcha_get_enabled_fonts();

    if (empty($fonts)) {

      // Config value might be wrong, try to reinstall the field.

      require_once __DIR__ . '/image_captcha.install';

      image_captcha_install();

      // Try again now.

      $fonts = _image_captcha_get_enabled_fonts();

      if (empty($fonts)) {

        $status = $status | IMAGE_CAPTCHA_ERROR_TTF_FILE_READ_PROBLEM;

      }

    }

    if (!empty($fonts)) {

      $readable_fonts = [];

      list($readable_fonts, $problem_fonts) = _image_captcha_check_fonts($fonts);

      if (count($problem_fonts) != 0) {

        $status = $status | IMAGE_CAPTCHA_ERROR_TTF_FILE_READ_PROBLEM;

      }

    }

  }

  return $status;

}