install_memcache_for_php7_on_centOS.txt

If you haven't solved this yet, I have a solution that worked for me. I'm on CentOS 7.x but it should still work for you, and anyone else wanting to use pecl-memcache with PHP 7 (not pecl-memcached as that's a completely different package).

As you have already discovered, you must use the Memcache PHP 7 port on GitHub for this.

Login to your shell and perform the following:

 1. wget https://github.com/websupport-sk/pecl-memcache/archive/NON_BLOCKING_IO_php7.zip
 2. unzip NON_BLOCKING_IO_php7.zip
 3. cd pecl-memcache-NON_BLOCKING_IO_php7
 4. /opt/cpanel/ea-php70/root/usr/bin/phpize && ./configure --enable-memcache --with-php-config=/opt/cpanel/ea-php70/root/usr/bin/php-config && make
 5. cp modules/memcache.so /opt/cpanel/ea-php70/root/usr/lib64/php/modules/
 6. echo 'extension=memcache.so' >/opt/cpanel/ea-php70/root/etc/php.d/memcached.ini
 7. service httpd restart
Some notes for the above:

Replace each full path that I've used with the appropriate full path on your own system. While I have /opt/cpanel/ea-php70/root/, you may have /opt/php-7.0.7/. If you have multiple PHP versions installed, as I do, running phpize may end up building using an old version of PHP. I discovered this after much trial and error.
To find out where your PHP modules folder is, you can run "/opt/cpanel/ea-php70/root/usr/bin/php -i | grep extension_dir"
You may not need to perform step 6 where I am creating a memcached.ini if you already have it loaded elsewhere.
You can verify if it was correctly built and installed using "/opt/cpanel/ea-php70/root/usr/bin/php -i | grep memcache". If you see various memcache entries, everything was installed successfully.
I hope that helps!