cocagne/paxos — pull request #2 by pjkundert (2013-03-09 19:12:59+00:00)
Title: On platforms without os.fdatasync (eg. OS-X), use fcntl.F_FULLFSYNC instead

Unfortunately, os.fdatasync doesn't exist on OS-X. The fcntl(fd, F_FULLFSYNC) is purported to yield approximately the same results, so provide a fall-back to that if os.fdatasync is found to not exist.