Firstly, check which php path is set. it should be /Applications/XAMPP/xamppfiles/bin/php. If not you can change it by PATH=”/Applications/XAMPP/xamppfiles/bin:${PATH}”. More detail here.
Before you begin make sure you have installed Xcode. Also, install the latest version of autoconf. this might help:
brew install autoconf
Next download the version of PHP you use in XAMPP from php.net. I am using 7.1.18. This version worked for me: php-7.1.31, I’m guessing if you follow the steps it might work for 7.0 or 7.2 as well. Do let me know if it does or doesnt, I’ll update this post. Do not use PHP 7.3 for Magento 2.3.0, it is not supported.
Extract the tar.gz file using (I extracted it inside ~/Downloads/ folder )
tar -xzvf php-7.1.31.tar.gz
cd into the extracted folder
cd php-7.1.31
change to subfolder ext/intl
cd ext/intl/
Run these commands to build the extension
/Applications/XAMPP/bin/phpize./configure --enable-intl --with-php-config=/Applications/XAMPP/bin/php-config --with-icu-dir=/Applications/XAMPP/xamppfiles/makesudo make install
You can now delete all files you downloaded and also the extracted folders.
Open /Applications/XAMPP/xamppfiles/etc/php.ini , and add extension=intl.so
本文地址：https://blog.csdn.net/jiabangok/article/details/107894896
