mac 下安装php的mongodb扩展，提示：homebrew/php deprecated

php.net 文档地址：
http://php.net/manual/zh/mongodb.installation.homebrew.php

原因：

The mongodb install has been removed from Homebrew. To install the mongodb extension you need to use pecl.

解决：

用pecl安装：

sudo pecl install mongodb

如果没安装pecl，以下安装pecl的文档地址：
http://pear.php.net/manual/en/installation.getting.php

主要步骤:

Use curl as shown below to download the go-pear.phar file or just download the go-pear.phar file via your browser.

$ curl -O https://pear.php.net/go-pear.phar
$ php -d detect_unicode=0 go-pear.phar

You’re now ready to configure PEAR for installation.

First you need to change the Installation Base.

So type 1, and then press Enter.

Enter /usr/local/pear

Press Enter.

Then, you will need to change the Binaries directory.

Type 4, and then press Enter.

Enter /usr/local/bin

Press Enter.

Once you have changed the Installation Base and the Binaries Directory, press Enter to install PEAR.

For a system-wide installation, you will need to execute the go-pear script with increased permissions. This is only recommended for advanced users.

$ curl -O https://pear.php.net/go-pear.phar
$ sudo php -d detect_unicode=0 go-pear.phar