I recently added a binary file as privdata (installed with `File.hasPrivContent`). When I `propellor --dump` the privdata on either Linux or macOS, the contents is correct. Spinning from Linux also works, but spinning from macOS installs a corrupt version of the file. The corruption looks like every valid UTF-8 sequence has been replaced with a single byte which is the lowest byte of the Unicode codepoint encoded by the sequence, so this must have something to do with encodings, but from staring at the source code I can't figure out what. The data from `--dump` is not corrupted which seems especially strange.
