These days (that's late 2021 for me!), for those running Ubuntu, and wishing to seriously tinker with PHP, the recommendation is to use Ondřej Surý's personal package archive for PHP.Beware of the mentioned caveats: you might end up with a slightly more unstable version of PHP which might not be updated correctly with future versions. In the case of aptitude, as shown on the other answers, you ought to be fine with just sudo apt install php-dev. A 'developer edition' of PHP, which some package managers call 'development headers'.A working C/C++ compiler - GCC or clang being the most popular options these days.

You will need at least a few prerequisites: You didn't specify what operating system you're using, and 90% of the answers assume Ubuntu/Debian Linux because of the apt-get install autoconf automake libtool m4 command that you posted (and over half expect you to be running CPanel), so I'm giving you a slightly more generic solution which ought to work on any Un*x clone (including Microsoft's WSL!).

Linux mint install ffmpeg