[arch-general] Replace python-magic from darwinsys with ahupp implementation

[Óscar García Amor]

Hi all!

Current in pacman we have python-magic from http://darwinsys.com/file/
with an unknown custom license. We have other implementation with MIT
license made by ahupp [1]. The second one is available in pypi and is
more advanced that the first one.

I have been checking the code of dependencies of python-magic and I
can see that deepin-movie and diffoscope supports well ahupp version.

Why not replace python-magic with diffoscope version, as can see in
AUR [2] this version is used for much more packages.

Greetings.

[1]: https://github.com/ahupp/python-magic
[2]: https://aur.archlinux.org/packages/python-magic-ahupp/
-- 
Óscar García Amor | ogarcia at moire.org | http://ogarcia.me