Install Memcached for MAMP on macOS

memcached-instructions.txt

 1. Install libmemcached with brew:
    > brew install libmemcached
    
 2. Install memcached with brew or pecl:
  - > brew install memcached / pecl install memcached*
  - When prompted for the libmemcached directory, press 'Enter' and the installer will automatically find it.
   
 3. Add the following extensions to your php.ini file:
  - > sudo vim /Applications/MAMP/bin/php/php7.2.1/conf/php.ini (replace your PHP version as necessary)
  - Add 'extension=igbinary.so' to the file
  - Add 'extension=memcached.so' to the file

 4. Restart your Apache server (use the MAMP GUI to stop & start the server)
    
 5. Start memcached with brew:
  > brew services start memcached
  
  
* If the pecl installation gives you an error related to zlib, run `xcode-select --install`