cava: Build fail on Gentoo Linux

@relrod iniparser version 3.1 and 4.0 has the exact same arguments, so i don’t know if a version detection is actually possible in a configure script. Would it be a sufficient workaround to use a compilation option?

So if you run something like:

./configure --legacy-iniparser

Would make it build with iniparser version 3.1

fwiw (@sedrubal you might be interested in this) for now I built this in a COPR:

https://copr.fedorainfracloud.org/coprs/codeblock/cava/

So: sudo dnf copr enable codeblock/cava && sudo dnf install cava should work on F22-24.