boxes updated upstream, fixes #30054

boxes compiled but was unable to run on 10.9 and 10.10 due to a 32 bit compiler issue. The issue has been resolved upstream (https://github.com/ascii-boxes/boxes/pull/11), but the changes are not yet in a tagged release. I added the 32 bit flags and a `head` value to the formula so that boxes can be installed with `brew install --HEAD boxes`.

One outstanding issue: it seems like the 32 bit flags are being ignored when `CC` is set to `ENV.cc`. If I explicitly link to `/usr/bin/cc`, the issue goes away. I dug around the environmental magic code that homebrew is using, but I couldn’t find a solution. Looks like `ENV.cc` and `clang` and `/usr/bin/cc` all end up linking to the same thing.