Add SyncDraw builds for FreeBSD and Linux, fix FreeBSD artifacts.
The AMD64 platform on FreeBSD is called amd64, not x64.
Synchronet now requires the libarchive development package (e.g. libarchive-dev on Debian-based Linux distros, libarchive.org for more info) to build successfully.
The AMD64 platform on FreeBSD is called amd64, not x64.