nmea(4) on OpenBSD

The text a86dca2838e7, as OpenBSD 6.3, OpenBSD 6.2, OpenBSD 6.1, OpenBSD 6.0, OpenBSD 5.9, OpenBSD 5.8, OpenBSD 5.7 shipped it.

NMEA 0183 timedelta sensor

nmea(4) on OpenBSD now