There has not been a lot of packages using this license, but the count
is increasing. Up until now, these packages have been marked as mit due
to how similar the two licenses are.
* make font derivations fixed-output where applicable
* fix dead links
* `stdenv.lib` -> `lib` where `stdenv` is not involved
* remove `meta.platforms = [ unix ]` and `meta.platforms = [ linux ]` because the restriction has no sense for data packages
