Remove code related to obsolete HW AirPcap

[AndersBroman]

The Riverbed® AirPcap Product has reached End of Availability (EOA) as of December 31, 2017 and it only supports older Windows versions.
https://support.riverbed.com/content/support/software/steelcentral-npm/airpcap.html

[infrastation]

@guyharris, these changes among other things remove the Windows-specific get_airpcap_handle_op_t member from struct pcap, would this require any backward compatibility provisions regarding NPF?

[infrastation]

These changes also remove a public Windows-specific function from the API:

PCAP_API PAirpcapHandle pcap_get_airpcap_handle(pcap_t *p);

This needs to be considered before merging.

[guyharris]

These changes also remove a public Windows-specific function from the API:

PCAP_API PAirpcapHandle pcap_get_airpcap_handle(pcap_t *p);

This needs to be considered before merging.

That function should not be removed, so as not to break the ABI.

Instead, it should should probably be modified to fail with an "AirPcap is not supported" error and marked as deprecated.

[guyharris]

@guyharris, these changes among other things remove the Windows-specific get_airpcap_handle_op_t member from struct pcap, would this require any backward compatibility provisions regarding NPF?

No - neither Npcap nor WinPcap uses that field.