Log Message:
update to BitTorrent 4.0.3

Also enable the enable_bad_libc_workaround by default for NetBSD,
FreeBSD, OpenBSD and Darwin.

Changes in this release:
- Identify trackerless torrent files
- Not saving pause/play state across invocations of the GUI
- Small fixes to windows installer and corrupt config file recovery
- A number of small bug fixes