[Font] Getting font folder on all platforms

[Flamaros]

I am searching the right way to find fonts folder for each 
platforms (Windows, linux, macOS X)

On Windows it's generally "C:\Windows\Fonts" but a direct access 
seems brutal, it's certainly expected to retrieve this path by 
using some register keys?

Is someone know how it works for linux and/or macOS X?

I need to be able to retrieve fastest as possible the right file 
from the font and family name.