Installation:

1. Copy redis.so from the appropriate subdirectory of this repo to /Applications/MAMP/bin/php/php5.x.x/lib/php/extensions/no-debug-non-zts-200xxxxx (Channge 5.x.x to your PHP version)
2. Add extension="redis.so" to the end of php.ini (Open MAMP click on File → Edit Template → PHP → PHP 5.x.x php.ini), for non-pro users edit /Applications/MAMP/bin/php/php5.x.x/conf/php.ini (Channge 5.x.x to your PHP version)
3. Restart MAMP.

How to do it yourself.

For 3.x

1. Mkdir include/php in /Applications/MAMP/bin/php/php*.*.*/, for example /Applications/MAMP/bin/php/php5.5.10/include/php.
2. Download php source file from php.net, if you want to compile extension for php 5.4.42, then download php5.4.42.tar.gz and extract to include/php dir.
3. Execute ./configure in include/php.
4. cd /Applications/MAMP/bin/php/php*.*.*/bin, execute ./pecl install redis for default version or ./pecl install redis-2.2.8 for special version.
5. Add extension="redis.so" to the end of php.ini (Open MAMP click on File → Edit Template → PHP → PHP 5.x.x php.ini), for non-pro users edit /Applications/MAMP/bin/php/php5.x.x/conf/php.ini (Channge 5.x.x to your PHP version)
6. Restart MAMP.

For 4.x

0. You may need install autoconf via brew install autoconf.
1. cd /Applications/MAMP/bin/php/php*.*.*/bin, execute ./pecl install redis for default version or ./pecl install redis-3.1.2 for special version.
2. Add extension="redis.so" to the end of php.ini (Open MAMP Pro dashboard， LANGUAGE-PHP，click 'Manually enable other extensions'), for non-pro users edit /Applications/MAMP/bin/php/php7.x.x/conf/php.ini (Channge 7.x.x to your PHP version)
3. Restart MAMP.