PhpBrew\Extension\ExtensionFactory::createFromDirectory PHP Method

    public static function createFromDirectory($packageName, $extensionDir)
    {
        $packageXmlPath = $extensionDir . DIRECTORY_SEPARATOR . 'package.xml';
        // If the package.xml exists, we may get the configureoptions for configuring the Makefile
        // and use the provided extension name to enable the extension.
        //
        // Currently only PECL extensions have package.xml, however It's the
        // best strategy to install the extension.
        if (file_exists($packageXmlPath)) {
            // $this->logger->warning("===> Using xml extension meta");
            if ($ext = self::createPeclExtension($packageName, $packageXmlPath)) {
                return $ext;
            }
        }
        // If the config.m4 or config0.m4 exists, it requires us to run `phpize` to
        // initialize the `configure` script.
        //
        // It's basically a fallback for extensions that don't have package.xml.
        // Generlly, The possible extensions using this strategy are usually
        // PHP's core extensions, which are shipped in the distribution file.
        // quote:
        //   the 0 there makes sure it gets into another stage of the buildprocess, the
        //   top IIRC, it was added @ 12th May 2001, 12:09am (10 months ago).
        //
        // http://grokbase.com/t/php/php-dev/023cpdc9k6/quick-summary-of-changes
        //
        // When config[0-9].m4 found, it might be an extension that can't be
        // installed as a shared extension. We will need to raise a warning
        // message for users.
        $configM4Paths = self::configM4Exists($extensionDir);
        foreach ($configM4Paths as $m4path) {
            if (file_exists($m4path)) {
                try {
                    $ext = self::createM4Extension($packageName, $m4path);
                    if ($ext) {
                        return $ext;
                    }
                } catch (Exception $e) {
                    // Can't parse the content, ignore the error and continue the parsing...
                }
            }
        }
    }