Install PHP gmp Extension in MAMP - 2020

Following instructions are for MAMP users only.

Step 1:

Check if you already have gmp is available in MAMP php

/Applications/MAMP/bin/php/php7.4.1/bin/php -i | grep gmp

Above command should print phpinfo in terminal, searching for gmp in phpinfo. If gmp not already available it returns nothing in terminal.


Step 2:
Download php from source https://github.com/php/php-src/releases pick the version which is matching with MAMP PHP version you have.

Step 3:
Copy the extension you want. Here we are copying gmp directory.



Paste it to /Applications/MAMP/bin/php/php7.4.1/include/php/ext

(Make sure to move to your MAMP php version directory)

Step 4:
Just cd into the extension gmp directory

cd /Applications/MAMP/bin/php/php7.4.1/include/php/ext/gmp

Then run phpize command

/Applications/MAMP/bin/php/php7.4.1/bin/phpize

Step 5:

./configure --with-php-config=/Applications/MAMP/bin/php/php7.2.8/bin/php-config

It outputs following


Then

make

Then

make install

Its installed now.

You can confirm it by

/Applications/MAMP/bin/php/php7.4.1/bin/php -i | grep gmp

gmp

gmp support => enabled

If you didn't see gmp support enabled, you may need to add following to php.ini.

This command will show you which php.ini file is used by MAMP php

 /Applications/MAMP/bin/php/php7.4.1/bin/php -i | grep "php.ini"

Add extension=gmp.so




Restart MAMP :)