Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r241231:

MFV: libpcap 1.3.0.

MFV: libpcap 1.3.0.

MFC after: 4 weeks

Vendor import of libpcap 1.3.0.

Add, remove and move files for the 1.2.1 import of libpcap

Submitted by: wxs