Use --with-swoole[=DIR] when compiling PHP.
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » https://pecl.php.net/package/swoole
to install swoole with mac os x
open your terminal
and use this commands
git clone https://github.com/swoole/swoole-src.git
cd swoole-src
phpize
./configure
make && make install
also find your swoole.so from folder swoole-src and move it
in to your apache and add full path in php.ini
like extension=your/full/path/swoole.so