* treewide: http -> https sources
This updates the source urls of all top-level packages from http to
https where possible.
* buildtorrent: fix url and tab -> spaces
* Implement libGL as a symlink package which uses libraries from libglvnd and
headers from Mesa (since ones from libglvnd are outdated).
* Use libGL_driver.driverLink treewide; add FHS paths where possible.
