The upstream tarball changed. Specifically, files now extract onto a
box2d-2.3.1/ directory rather than Box2D-2.3.1/. The files themselves
(and their contents) seem to remain the same.
(cherry picked from commit a8b85f6d68d4fc96a0f8473aa38a3e773b82c4f0)
According to https://repology.org/repository/nix_unstable/problems, we have a
lot of packages that have http links that redirect to https as their homepage.
This commit updates all these packages to use the https links as their
homepage.
The following script was used to make these updates:
```
curl https://repology.org/api/v1/repository/nix_unstable/problems \
| jq '.[] | .problem' -r \
| rg 'Homepage link "(.+)" is a permanent redirect to "(.+)" and should be updated' --replace 's@$1@$2@' \
| sort | uniq > script.sed
find -name '*.nix' | xargs -P4 -- sed -f script.sed -i
```
Sandro