I'm not sure if HOME can ever be undefined on OSX, but the code seems to think it might not be. If it was, this code would set the log directory to /Library/Logs, which is probably not what is wanted. Instead of failing silently, it should do an assert with error or have some other fallback.
Take a look here: https://github.com/OSVR/OSVR-Core/blob/master/src/osvr/Util/Log.cpp#L127
I'm not sure if HOME can ever be undefined on OSX, but the code seems to think it might not be. If it was, this code would set the log directory to /Library/Logs, which is probably not what is wanted. Instead of failing silently, it should do an assert with error or have some other fallback.
cc: @godbyk