为什么在PHP7上的ElephantIO没有认识到我使用OpenSSL编译

Question

I just compiled PHP7 on Ubuntu 14.04 with the --with-openssl flag and it's fully operational. I installed Elephant.io with Composer, but ran a test and got this error.

Fatal error: Call to undefined function ElephantIO\Payload\openssl_random_pseudo_bytes() in /var/www/html/vendor/wisembly/elephant.io/src/Payload/Encoder.php on line 42

Here is my test code.

use ElephantIO\Client,
    ElephantIO\Engine\SocketIO\Version1X;

require __DIR__ . '/vendor/autoload.php';

$client = new Client(new Version1X('http://localhost:3000'));
$client->initialize();

Here's the command I ran to configure the build before compiling PHP7.

./configure
--prefix=$HOME/php7/usr
--with-config-file-path=$HOME/php7/usr/etc
--enable-mbstring
--enable-zip
--enable-bcmath
--enable-pcntl
--enable-ftp
--enable-exif
--enable-calendar
--enable-sysvmsg
--enable-sysvsem
--enable-sysvshm
--enable-wddx
--with-curl
--with-mcrypt
--with-iconv
--with-gmp
--with-pspell
--with-gd
--with-jpeg-dir=/usr
--with-png-dir=/usr
--with-zlib-dir=/usr
--with-xpm-dir=/usr
--with-freetype-dir=/usr
--enable-gd-native-ttf
--enable-gd-jis-conv
--with-openssl
--with-pdo-mysql=/usr
--with-gettext=/usr
--with-zlib=/usr
--with-bz2=/usr
--with-recode=/usr
--with-mysqli=/usr/bin/mysql_config

The Ubuntu packages are there I think. Here are my openssh* packages!

openssh-client openssh-sftp-server openssl-blacklist openssh-server openssl openssl-blacklist-extra

Any ideas? I am stuck and new to compiling PHP.