pcap_free_datalinks(3) on FreeBSD
The text 4ac2df7cdcbd, as FreeBSD 10.4-RELEASE, FreeBSD 10.3-RELEASE, FreeBSD 10.2-RELEASE, FreeBSD 10.1-RELEASE, FreeBSD 10.0-RELEASE, FreeBSD 9.3-RELEASE, FreeBSD 9.2-RELEASE, FreeBSD 9.1-RELEASE shipped it.
get a list of link-layer header types supported by a capture device, and free that list