title: Can't install php Intl extension on MacosX
body: <p>I'm following this <a href="https://pagegwood.com/web-development/how-to-enable-intl-extension-mamp-osx-10-9-2/#%F0%9F%8C%B4" rel="noreferrer">link</a> to install this PHP extension but I'm stuck in the middle.<br>
  When I try to run this command <code>pecl install intl</code> I get this message:<br></p>
  <pre><code>Specify where ICU libraries and headers can be found [DEFAULT] :
  </code></pre>
  <p>And I don't know where the ICU libraries are located.<br>
  If I press Enter I get this error:<br></p>
  <pre><code>configure: error: Unable to detect ICU prefix or no failed. Please verify ICU install prefix and make sure icu-config works.
  ERROR: `/private/tmp/pear/install/intl/configure --with-php-config=/usr/bin/php-config --with-icu-dir=DEFAULT' failed
  </code></pre>
  <p>How can I locate the correct path of ICU libraries ?
  I'm using High Sierra and MAMP with PHP version 7.1</p>