How to install and run phpize

I have been meaning to install ffmpeg as an extension to my PHP setup. So before I can install it, I need to phpize it. I installed php5-dev by sudo apt-get install php5-dev. But now when I run phpize I get the following error :

Cannot find config.m4. 
Make sure that you run '/usr/bin/phpize' in the top level source directory of the module

The location of my php.ini is /usr/local/zend/etc/php.ini

From another online resource I tried this

sudo apt-get install autoconf automake libtool m4

But all of them are already installed.

Locate config.m4 didn't return anything.

Any pointers here how I can get phpize and thus, ffmpeg up and running?


For recent versions of Debian/Ubuntu (Debian 9+ or Ubuntu 16.04+) install the php-dev dependency package, which will automatically install the correct version of php{x}-dev for your distribution:

sudo apt install php-dev

Older versions of Debian/Ubuntu:

For PHP 5, it's in the php5-dev package.

sudo apt-get install php5-dev

For PHP 7.x (from rahilwazir comment):

sudo apt-get install php7.x-dev


yum install php-devel # see comments