`adjust_format()` should use OS and not ARCH. In Windows, `$OS` will be calculated to be `"windows"` while `$ARCH` will be `"386"` or `"amd64"` (most of the time). `$ARCH` will surely never be `"windows"`.
This mostly aims to document how everything was generated, and the steps
necessary to re-generate the same files verbatim; the goal is to figure
out how to reproduce the files as they currently are. The exception is
that we strip out the timestamp out of install.sh.
