s://sourceware.org/systemtap/">SystemTap</a> on Linux, or DTrace on macOS) are found.
See also <a href="https://github.com/h2o/h2o/wiki/macOS">wiki/macOS</a> to use DTrace on macOS.
</dl>
<dt><code>-DWITH_H2OLOG=<i>on</i>|<i>off</i></code></dt>
<dd>
This option instructs whether or not to enable <code>h2olog(1)</code>> support.
It is turned on by default if the prerequisites are found.
See also <a href="./configure/h2olog.html">h2olog</a> for details.
</dl>
<dt><code>-DOPENSSL_ROOT_DIR=/path/to/openssl</cod